slave treasure and drink their Master's semen is very common in BDSM.
This is a common request as the end to normal oral sex, but when
there is a Master / slave relationship, Masters frequently like to
use this power to force the slave to drink their cum.
Most times when a Master finishes oral sex by cumming in his slaves
mouth, he will want her to swallow what he has provided. In
addition, due to the fact that women often do not want to do this,
sometimes Masters will finish early from normal sex just so that
they can force their slave to consume it.