I've been jerkin off since I was 12, and I learned from a friend. He taught me by showing me. Then it became mutual masturbation. After he taught, like, a month later, he asked if I wanted to jerk him off while he jerked me off. I said "shure". I think that, if you wanna try it, be direct and don't beat around the bush (no pun intended). Just be all "Hey, have you ever jerked off with another dude before?" and take it from there. To any and all who have yet to jerk off with a friend and want to, good luck!