Only 12cm,
Only 12cm said:
Recently my girlfriend (now 19) told me that her dad has been fucking her for the past 2 years, since her 17th birthday.
This doesn't strike me as implausible. It's socially taboo for fathers to fuck their daughters, as everyone knows (mostly, presumably, because incest can result in offspring with severe birth defects if the daughter's [/father's] birth control fails), but it isn't all that unusual.
Only 12cm said:
We have been together since April of this year, and she doesn't allow me to fuck her. I'm only allowed to lick her pussy and asshole.
This doesn't strike me as implausible either. Apparently a heavy majority of university and college women now expect their boyfriends to suck their pussies, but do not allow them penetrative intercourse. This can be considered good training for marriage, per the following quiz.
Q: What is a married man's proper place?
A: On his knees with his face between his wife's thighs, his lips sucking her pussy, and his tongue giving her cunnilingus.
Q: If a woman is not entirely satisfied with her husband in his proper place, are there other proper places?
A: Yes. On his knees with his face between her cheeks, his lips kissing her asshole, and his tongue giving her analingus.
It sounds like you're doing well on both fronts, so to speak. Keep up your good work.
Only 12cm said:
But you know what... I find it arousing that I lick her pussy/ass when only a few hours earlier her dad had fucked her.
As you should.
Only 12cm said:
She also always comments on my small penis size and wants me to be fully shaved down there, because I'm not a real man like her dad.
Well, if your woman has told you that's what she wants, you'd better get on it and shave your genitalia. When she tells you she wants you to do something, it's best to do it promptly. You may incur her displeasure (or worse) if you delay.
—Custer