top from the bottom

Basically, it is a description of sexual nature that could involve any number of acts: when a dominant person takes a submissive role but still remains in charge while the actual submissive person takes a dominant role but still takes orders.
> A dominatrix is said to "top from the bottom" when she lets her submissive tie her up and perform oral sex on her, but all the while she is telling him how she likes to be licked and he does it how she says to.