A woman in our group found she had lost a tiny screw from her glasses. People looked around carefully but could not find it. Someone suggested that it had somehow gotten into her clothes - the wrinkles, the cuffs, somewhere. I asked her if she wanted me to undress her and she immediately said, "It's not pretty!". I never did get a chance to see her nude but since we are post-70 years of age, I think I know what she meant.
I think we are too much in grip of biological standards as we age. Sure, we know at a glance when some 25 year old is a fine-looking man or woman. Great structure, great posture, great skin, great spirit and confidence. That is all to the good and I would be silly to be against what works and is attractive.
I am only pushing for oldsters to use their brains as much as their inborn reactions. We know when we are too old to make babies or to parent infants. But sometimes, we are still alive enough to benefit from touching and good sexual practice. I haven't done any research on the benefits of good use of bodies at post-70 ages but I bet there is already some data and results that show good activity in bed is helpful for lifting the spirits and quickening the pulse. There is certainly good data on the value of treasured and uplifting relationships.
I say try to concentrate on your breath and not your belly. We all have sags and wrinkles and they are quite kissable. Concentrate on sensations and not pin-ups of stars. We can do ourselves some good and at the same time pave the way for latter senior citizens.