New to this site, but find most of the posts on all topics fascinating. I was a little reluctant to state my age, but now that I see myself in such congenial company, I can state that I am 75. This is a useful thread because there is a significant bias against "sexy seniors" in many areas of society. I see lots of articles on the amount of sexual activity in Senior's Residences. There is always a little element of "Can't believe those old fogies are still at it!" in the tone of the articles.
Mathgirl, I applaud you. You could lead a one-woman crusade to remind everyone over the age of 60 that life can still be rich and satisfying in all aspects, including sexual.
If penetrative sex is just not on, there are, as you point out, a myriad of ways to enjoy intimacy with a partner. just the sheer tactile gratification of snuggling naked with another individual is therapeutic.One's enjoyment of sex, and kinks, is no doubt to some extent dependent on the overall quality of life enjoyed.
I ride motorcycles, workout frequently, bicycle, walk, eat sensibly and generally stay active. My S.O. prefers to keep our sexual encounters at a once per week level. I can live with that, because she is a loving, enthusiastic, sex partner. We have been together 13 years, and she has come a long way, considering she was taught by nuns. And, yes, before you ask, I would love to have her dress in a nun's habit with sexy lingerie underneath. It's a cliche, but sometimes you can't beat the old standards. She is 70, and in my eyes, gorgeous. I never tire of telling her so, and I'm sure she now believes me, although she claims my eyesight must be failing.