She doesn't measure the consequences and the girl regrets it.

When women are very horny they don't think clearly and they don't measure the consequences. The boyfriend fucks her pussy by sticking his dick to the bottom and making the balls bump against the girl's ass. When she is about to ejaculate, without thinking she puts her cock in the mouth that is covered with her vaginal juices and ejaculates in the mouth of the girl. She had never let him ejaculate in her mouth because it always disgusted him, and now she gets the great prize of tasting her own pussy also apart from semen!