I had a mate who used to flog on the carpet.
After a few years of such activity he moved house, but he wasn't able to get the stains out.
So, fellas, some friendly advice: don't ejaculate on the carpet, it don't come out.
p.s. Instead you might like to consider the towel, the piece of paper, the sock or even the time honored tissue for an effective and hassle free semen receptacle.
p.p.s. If you're really brave, you might like to try a woman. (WARNING: May take significant convincing. Has tendency to be less disposable and can be quite expensive.)