#mating plug

Imagine finding out how bat-like the space vampires are after the two males drain the guards before breeding you. The first lays you on the bed of his “coffin” before parting your legs and leaving a mating plug. Meanwhile, his companion coaxes you into fellating him. 

Some animals and insects, like squirrels and bumblebees, use a "mating plug" to prevent other males from inseminating females they have already mated with. – WTF Fun Facts Source: http://www.bbc.com/earth/story/20170419-the-largest-and-smallest-sex-cells-on-the-planet