I've had two good jack off buddies as an adult. One was a straight friend with a big thick cock that I only got to see hard went we shared a room on trips. I saw him all the times in the gym shower but was grower, good blood flow he always said. No cock touching but he always had a ragging hardon. I alway leaked a lot of precum during those sessions.
Other guy was a friend who would wait for me to put on porn after going out. He liked playing with his hole, so I would lube my finger and slowly slide it in him. Supposedly he was a top so I never got to feel that tight hole around anything other than my finger. And although he spent the night a few times, he seemed to be one of those gay guys that just like jerking it.