I'm looking for what was basically a PWP. I know it was AO3, just can't find it. It's a fic where Steve and Tony got captured by bad guys and were tied up together. Well, they were tied to each other, chest to chest. Steve gets hard and he ends up rubbing off against Tony. Steve is apparently very sensitive and once he gets hard kind of stays hard and comes multiple times. Clint is the one who finds them and rescues them after.
Trigger Happy by KandiSheek