sperm pillow
That is actually my pillow, which receives my sperm on a regular basis. A sperm pillow can be used instead of a cum rag. You might also try the effect of calling your girlfriend (or gay boyfriend) your sperm pillow. In fact, there seems to be no such concept in the English language, but we do create things with our thoughts, so I thought it might be a good idea to add it.
Hi sweetie, would you like to be my sperm pillow tonight?