Control of the pelvic floor is important for both men and women. Because these group of muscles are near the sex organs they can greatly affect our pleasure.
I heard about this when I worked in several hospitals in my youth. At 18, I remember my immediate interest, surprise at the fascinating new information; my parents never talked about this type of stuff at home.
For women these pelvic floor muscles can be weakened at childbirth. Kegel exercises can strengthen these muscles.
http://www.webmd.com/women/tc/kegel-...topic-overview
For women with damaged pelvic muscles, or for those who just want to improve their sex lives and be able to grab the little guy: the following video may get the idea across, or just look up Kegel exercises.
https://www.youtube.com/watch?v=v7Y6px6cIlw
Men should be able to flex the pelvic muscles between the base of the scrotum and the anus. The kegel exercises help to strengthen these muscles and provide a more intense orgasm and improved erections. When the penis is erect the exercise can move the penis. All guys should thoughtfully use a kegel exercise several times a day. I use it every time one of my staff ladies walk into my office, driving down the street, at the grocery store while shopping: whenever I see a pretty lady. It can be the secret exercise for all big guys to keep the little guy fit and strong.
Before viagra kegel exercises can help tighten the muscles around the penis:
http://www.webmd.com/sex/video/ed-exercises-better-sex
The last referenced video is highly recommended for all.
JR