Hump Day is a term, which usually describes the middle of the Monday through Friday workweek, hence getting over the hump.
However, it has taken on a more risqué and naughty meaning related to sex.
Terms such as humping, doing the horizontal tango, getting freaky, bumpin and grindin, hittin that, and other ones I won’t mention, are now seen and heard frequently. They are used to describe what used to be considered a special and intimate time. Now, it seems that true intimacy and connection between couples has been abandoned in favor of frantic and temporary groping and coupling.