This is much like cherry popcicle. When a girl who is on her period gives a very willing man head and takes the load in her mouth and holds it there for a while. The man proceeds to eat to eat her out (remember, she is on her period), collecting a delicious load in his mouth. Finally, to top it all off, the two make out and swirl a "rainbow room" around inside their mouths.
"She was really craving a rainbow room, but I refused to put that nasty bloody shit in my mouth."