I’ll start: My first GF and I didn’t use protection. We used the pull out technique. FOR AN ENTIRE YEAR! I was 19 and could have ruined my life then and there.
When I was in the Army, one time we built a racetrack, complete with jumps, for the bulldozers. One person drove, the rest of us just hung on with our bare hands, with the moving treads a few feet below us, no seatbelts, no safety harness, nothing. The motor pool Sergeant said we could do it as long as we all wore our kevlar (helmet) (he was also nuts and didn’t care about shit). That no one fell off and got crushed under the treads is a miracle. God, we were so dumb. Helluva ride, though.