Abella has the answer, maybe?

Ok I have not cum like that when I had sex with Cherie and Mrs Jackson, also you never that feeling before just as you came in her so what is different could it be age she is only in her early 20's at most, were Cherie and Mrs Jackson are late 30's and early 40's. At this point Abella comes to and notices her stomach and like any normal girl freaks the absolute fuck out, looking panicked, hyper ventilating and on the verge of tears you step in to calm the girl down.

Abella calm down it is just a large amount of cum give it a while and you should be able to expel it with a little effort, now tell me about yourself please. Immediately Abella calms down and now looks at you with something like worshiping/pleading, "I am 26 years old, in my final year of university, I live on my own, have had this job for a 2 years now to help pay off my education fees, I have no idea why I let you fuck me I am normally a good girl and even then I always use condoms as I cannot use oral contraceptives. With the amount of cum in me and that it is my most fertile time at the moment I am almost certainly pregnant, I am very scared of having to raise a child alone please don't leave me alone".

Right that last statement gives you a possible answer, the smell that had you follow her must have been you detecting that she was fertile and you released the scent when you thought about sex thinking back the other times it has happened was during a sexual moment. So this could mean you will only get rid of the itch if you knock up a girl, well that sucks on one level but that feeling when you came in her was beyond anything you have ever experienced, more experimenting is needed before you can confirm this is true this could all be a massive coincidence. "Abella here is my number call me later, but I have a few more places to shop at today". Call him he is a good person and reliable, not to panic if she is pregnant and everything is ok.

Leaving the changing room you quickly look around to make sure no body heard what was going on only to realise something is up with that why is or did no one come to see just what was going on.