2. She must be proud of you
Women share their bodies with men they admire & respect.
If she pities you, forget about it.
If she's embarrassed by you forget about it.
She must think you're smart, handsome, and have an awesome personality.
Be going places in life... the slacker / adolescent angst won't get you what you want.
This guy's ho is using him to feed her fragile ego. If he actually wants to get his dick wet he'll have to turn the power tables. She must, subconsciously or consciously, want to surrender her body to the cool guy-- even if he is related.
3. Her friends are the key to her ass.
Women are extraordinarily vulnerable, by male standards, to groupthink. This applies even to 'conversion disorder' (aka mass hysteria) and, to our purpose, sexual attraction. Whenever a public health panic hits women more than men, the cause is almost always a psychosomatic illness.
This is VERY helpful in bedding any woman; even related women.
When one woman finds you attractive, others will too BECAUSE of the other girls liking you!
Whereas if two men like a woman, it's because they independently think she's got a nice face and good body ratios. The other man's attraction has nothing to do with it.
Do you see the difference?
If so, you can then see that if her friends find you attractive then your target will too. If her friends tell her "oh, user is so hot! does he have a girlfriend" then her groupthink is triggered.
Trip that wire user and your chances just went WAY up. Throw in a little alcohol and you've got a real shot.