Due to an injury I had my prostate massaged two times a week for more than six months by a licensed physical therapist and masseuse.
The on my back knees pulled up just above my chest position was how she did it.
She was a very mature older lady and we never did any sex stuff.
After the first few times she stopped trying to cover my privates with a small towel to protect my modesty.
This mean discharge all over me and sometimes her left forearm that was wrapped around my legs. She never worried about that and always cleaned me up with warm wet towels.
Sometimes my thighs would trap my erection behind them leaving my penis near her face. She never worried about it or moved it.