The towel that is kept handy by your bed side that is laid on top of the bed to prevent semen, lube, female ejaculate, Santorum
or period blood from getting on the sheets.
Man, good thing we had that Spontaneous Jack Towel handy. That was a messy round of love making. The mood was not killed becaues it was handy by our bed side and now I can go to sleep knowing that I am not going to roll over into mixture of my semen, your ejaculate, and lube.