This is found in Comic Unreal 2008-02 Vol. 11. The basic scene is about some kind of succubus trying to have sex with the main male character. In order to do this, the succubus take the hair from the male character's love interest, put it into a potion, and uses the potion to transform herself into an older busty sexy version of said love interest. The early scene includes a lot of loli futa sex...something I'd rather not post here.
Before & After
Scene After Transformation (without loli & futa intro)
http://www.badongo.com/file/8507590