From the initialism CEI: “Cum Eating Instruction.”
CEI (plural CEIs)
Basically, CEI stands for Cum Eating Instruction. It’s exactly what it sounds like: a BDSM kink where a submissive (usually a guy) is ordered to eat his own semen. It most often happens with a female dominant, frequently during things like jerk-off instruction (JOI), but like most things in the kink world, there aren’t really hard-and-fast rules on who does it or how it happens.
Usually, this plays out in one of two ways. Either the sub knows going in that he’s going to have to clean up after himself, or the Domme waits until right after he finishes to drop the news. Both styles have their perks; some guys like the dread and anticipation of knowing it’s coming, while others get a rush from the surprise. The psychological aspect is huge here — it creates this intense mix of wanting release but being nervous about the humiliation that follows, which often makes the orgasm even stronger.
A lot of Dommes like to keep their subs on their toes by not making it a guarantee. If the sub never knows if this is the time he has to do it, the suspense adds a whole other layer to the session. While it’s usually an immediate instruction, some Doms like to get creative, maybe telling the sub to mix it into their food or coffee to consume later in the day, stretching out that feeling of control.
Here is the most important part: this absolutely needs to be talked about before the clothes come off. CEI is an intense flavor of play, and it’s definitely not something to spring on someone as a surprise unless they’ve already given the green light. If a sub isn’t into it, forcing the issue can instantly kill the mood and ruin the trust. A Mistress should only ever give that instruction if she knows for a fact that her sub has a genuine desire to explore that specific fetish.