Felching

Felching is a human sexual practice in which one person sucks semen or other fluids out of the vagina or anus of a another person. The acts of sucking the semen and then passing it from the mouth of one person to a third person is called snowballing. However, snowballing usually relates to semen ejaculated in the mouth following fellatio.
Felching can also mean the licking or sucking of another person's anus, similar to the act of anilingus.