Two. When I was 17, I gave my best friend a blowjob in the wee hours of the morning when he was sleeping over; then, in the evening, I gave/received oral and had PIV sex with my girlfriend (who didn't know about my best friend and me). This actually happened twice in the same week. It was exhilarating — and kinda surreal. i don't think I've ever been quite as sexually blissed out before or since.