don't see why you skipped that whole secondary story there...it's kind of a huge deal and basically makes part 1 obsolete. going to assume you're telling the truth, if you're just a storyteller kudos mighty fine story.
Anyways, you're cousin seems to be down for you playing with her, maybe try to get her to reciprocate (thats the damn word i couldnt think of on that other thread) the favor, play with you. or just wear very loose bottoms (pants, shorts, a sock on your cock) whatever floats your boat captain jacques coustea, play with her and assuming you get hard doing that, try not to hide said boner maybe rub it once or twice ocasionally. and Bam handy/BJ (bj most likely if you get a little fresh with your mouth on her)
Now the question about anal/vaginal? don't ask me that all comes down to you and her willingness.