When a character's apatite for sex, whether giving it or recieving, seems bottomless and unquenchable usually leading to cum inflation. The character must be willing for intercourse, and not being forced into it or distressed by it.

Often times the partner can express unwillingness to continue intercourse, but the insatiable character will continue to either penetrate or service their unwilling partner; however, a insatiable character doesn't need a partner for this tag, they could show behavior fitting this tag by begging for more sex while looking well used, or be furiously masturbating with the intent to milk themselves, or to simply stimulate themselves while begging for sex and looking crazed.

Large amounts of cum is also a fun bonus.