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 . The act of sucking the semen and then passing it , through mouth-to-mouth or open-mouth kissing , is often referred to as `` snowballing '' ; although the latter is typically associated with semen ejaculated into a mouth from fellatio .