Me (20M) and my gf (21F) bought a set of cards for couples. Not just regular cards. The ones with "act out your favorite sex position" or "you must do whatever your partner asks for 5 minutes" kinda stuff. And so she got a card with "lick whipped cream off your partner's nipple". We both got off the bed and made our way to the refrigerator. She took out whipped cream and sprayed a little bit on my nipple. When she started to lick and suck I thought my brain was going to melt. I never thought my nipples can be that sensitive. I got hard immediately. After she finished she looked me in the eye and asked ,,Did you like it?" while licking her lips seductively. I nodded and said ,,Can you do it while we are having sex?". She agreed of course. Now almost every time when I'm getting a hand job, I'm also having my nipples sucked. Her technique is making me melt. I'm always cumming super fast and a lot. So my message to all man is: ask your woman to suck your nipples. And to all women: suck your man's nipples.