Jane Fonda and Lily Tomlin have had decades to study for their roles as confidantes on Netlix’s “Grace and Frankie.” They’ve been friends since the late 1970s, and they collaborated on 1980’s “9 to 5” with Dolly Parton.

As Grace and Frankie, Fonda and Tomlin play women in their 70s whose husbands, Robert and Sol (Martin Sheen and Sam Waterston), have left them to marry each other. Grace and Frankie start out as rivals, but eventually become roommates, besties and business partners. The third season, now streaming, shows them selling vibrators designed for older women.

We spoke with Fonda and Tomlin about love and friendship, being an aging woman in Hollywood and what it might take for women’s sexuality to be taken as seriously as men’s. The following interview has been edited for length and clarity.

Lisa Bonos: My mother and I both watch “Grace and Frankie.” I’m a millennial; she’s a baby boomer. Do you have a sense of the demographics the show is reaching and why its appeal might span generations?

Fonda: What you just described – daughters watching with mothers and sons watching with mothers – it apparently is very common. But also apparently on college campuses, it’s very popular as well. And of course older women and men really like it. What Lily and I hear very often is women saying to us: “It makes us feel less afraid of getting older. It makes us feel hopeful.” That makes you feel good.

Tomlin: We never expected it to hit so many chords for so many different people.

Bonos: The show has made me think a lot about the longevity of female friendships versus the longevity of romance. Jane, you’ve been married several times. Knowing what you know now, what might you tell your younger self about marriage versus friendship and what to expect from those kinds of relationships?

Fonda: Well you know, it’s very different for different people. I was dealt a hand that didn’t lead necessarily to successful relationships. My dad was married five times. I guess I just don’t know how to do it very well. I’ve been married three times; it will never happen again. But I know what it feels like to have the rug pulled out from under you, and to feel like your life is over and consider suicide and all that kind of thing. So I kind of identify with what happened to Grace and Frankie; I know what that feels like.

I also know that, like what happened in the series, you shouldn’t give up. For a while, you have to stay close to the wall and be careful who you spend time with, and really take care of yourself and stay healthy. You think you’re being broken, but actually you’re being broken open, and life can get way better than you ever expected after the huge tragedy happens.

Bonos: Lily, you’ve been with your partner, Jane Wagner, for over 40 years. What’s your secret?

Tomlin: Commitment. Just willingness to go the distance. Caring about somebody, respecting somebody. Just wanting to build on that. On March 31, we will have been together 46 years.

Bonos: Jane, do you have a Frankie in your real life?

Fonda: My other self; I have a Frankie inside me. Well, I have Lily. Off-camera, she’s my friend. Catherine Keener is kind of Frankie-ish. I try to keep funny people around, because I come from a long line of depressed people.

Bonos: Lily, you and Jane go way back.

Tomlin: I’ve been a fan of hers since before I met her. I had a Klute hairdo when she did “Klute.” I met her when she came backstage when I was doing “Appearing Nitely” at the Ahmanson Theatre in L.A. That was about ’77 or ’78. Next thing I knew, she asked me to be in “9 to 5.” We’ve been friends ever since. We’re friends because I just love her. I know Jane has my back whenever she can.

Bonos: In the third season of “Grace and Frankie,” your characters have trouble getting a business loan. Most of the banks they speak to assume they won’t be around long enough to pay them back. Have there been moments in Hollywood where others have been shortsighted about the longevity of your career – and how did you respond?

Fonda: I left the business at age 50, and I came back at age 65. It’s been an unusual situation to re-create a career at that age. But ageism, unfortunately, is still alive and well. And one of the things that Lily and I are proud of – and want to continue with – is showing that you may be old, you may be in your third act, but you can still be vital and sexual and funny … that life isn’t over. Even when I was younger, I wanted to give a cultural face to old age.

Bonos: Speaking of sexuality, the discussion of masturbation and female pleasure on the show is fascinating and different from other things we see on TV. What is still considered taboo, though, in regard to seeing women as sexual beings on television? And how do you see that shifting?

Fonda: I think more things should be taboo. I think everything is much sexier on a big screen and small screen when it’s more suggested and hinted at than when it’s full-out. I think those movies before the censors took over – when women were strong and sexy, the Barbara Stanwycks, the Norma Shearers, the Bette Davises, Greta Garbo. That was sexier, I think, to not show everything.

Tomlin: Every TV show we’ve been on (to promote “Grace and Frankie”), we’d been cautioned not to say “vibrator,” to say “sex toy.” On the “Today” show, we talked about it anyway, but they were on the discouraging side.

Bonos: You can’t say “vibrator” on TV and yet Viagra commercials are everywhere. Why is there so much discomfort?

Tomlin: I think it’s female versus male sexuality. That’s a celebration of the penis, Viagra. They have a special drug. I think it’s the fact that we’re supposed to be older women.

A lot of the culture thinks of the vibrator as a denial of the penis, which I don’t think it is. Years ago, Mrs. Beasley, one of my characters, did a monologue advocating for vibrators. This was back in the 1980s. I did it for the first time at a fundraiser for (Walter) Mondale, and even people in Hollywood were a little taken aback.

There’s something too intimate about masturbation; it’s still an issue that’s something of a deterrent. But not with young people! Millennials, by and large, seem to be more enlightened.

Bonos: Jane, what does this story line mean for you? Do you see female pleasure as connected to women’s health and fitness?

Fonda: It means you don’t have to have a man! (Masturbation) is especially useful for older women, because men die sooner than we do. And so: Use it or lose it. It’s not critical that every woman wants to stay juiced up. But if they do, it’s perfectly fine. It’s a lot easier to feel sexy and perform safely when you’re flexible and have a certain amount of strength left. If you keep moving – walking, staying strong, doing squats – then having sex is both safer and more pleasurable, and you feel more empowered and better about yourself.

Bonos: As far as depictions of single women on television, or senior women on television, what kind of characters would you like to see more of?

Fonda: Good, multidimensional, complex women – of any age, but especially older women. I’m so happy about “Big Little Lies,” for example. Seeing the complexities of women’s lives, and seeing women interacting together, is really great.

Bonos: In terms of women’s sexuality as represented on television, what would you like to see?

Tomlin: Just people taking it as a matter of course. It should be expected. It shouldn’t be threatening or so fearful.