Hahahaha, where the hell is this from? XD

I want to know as well XD

My guess, base on the style of the drawing, would be CCC doujin. Crazy Clover Club has some pretty nice doujins, ranging from comic, drama, and of course, xxx. This one is probably translated by one of the folks in a forum called Beast Lair.

Source for this one would be good. That, and "Melty Bra". They were hilarious.

You can find Melty Bra and some other translated Tsukihime and FSN doujins here:
http://koti.mbnet.fi/cruzz/Tsukihime/

Thank you, I appreciate it a lot.

MeltyBra was also posted to Danbooru.