Lying on your mouth
Lying about giving/receiving oral sex to/from someone, which includes sucking dick, eating pussy, licking ass, etc.
WOMAN: You know that girl said you ate her out. But, I knew she's lying on your mouth because you was home the whole time.
MAN: When you see that chick again, have her come to my office. She's gonna answer to me for that.
MAN: When you see that chick again, have her come to my office. She's gonna answer to me for that.