In a Woody Allen movie, one of "the early funny ones," a woman compliments on his sexual performance and he modesty thanks her, saying " I practice when I'm home alone."
On the other hand, just as men have an architecture that allows them to pee almost anywhere at any time, boners arise spontaneously or can be raised by hand, either start providing all the readiness needed for a massage with a happy ending, whether outdoors, in a men's room, or anywhere else the urge appears and the horndog is brave enough.
And let's not forget another classic line from Woody Allen; "Don't knock masturbation. It's sex with somebody I LOVE"