Toxic Rusty Reversal
When you put your lips to your sex partners anus, and he or she takes a fairly large fart into your mouth as you inhale, causing the taker to vomit into the partners rectum. Then the partner forces the vomit back into the mouth of the taker. Causing a chemical reaction created by the bile.
" Hey Johny, have you ever done a Toxic Rusty Reversal ,cause that shits wacked".