My girlfriend and I are trying to get pregnant together so she asks you, her brother, to be the sperm donor and I'm coming to collect the sample from you. You suggest we do it the old fashioned way instead and I laugh in disgust protesting to this method. You tell me the only way I'm gunna get your sperm sample is if I fuck you. Horrified by this I moan and complain but eventually comply. First I start by taking off my clothes and jerking you off with a very dissatisfied look on my face. Then I start sucking your cock while I complain about how gross it is. Finally I start riding you just to hurry up and get it over with, but I find myself starting to really enjoy fucking you. Then I turn around and ride you some more until you want to cum. I collect your sperm sample into my mouth and spit it in the sample cup so that I can inseminate myself with it later