Parties where several girls wear a different color of lipstick then each proceeds to give one or more guys a blow job. The multiple of colors left on each guy's penis resembles a rainbow.
I've been to two rainbow parties now. I didn't last long at the first one seeing all of those girls giving head at the same time with the different lipstick. Julie had me first with yellow lipstick, and I blew my load in her mouth within a minute or two. When my penis was less sensitive a little later, Karen gave me another one with her bright blue lipstick. Since I didn't cum, Pamela took over with her green lipstick when the bell was rung. She asked me to cum on her chest if I needed to, and after I did, I was done for the night.
At the second party, I was more relaxed, and before the end of the night had let each girl leave her mark.