Next time you see a bird you want to fuck, just go up to her and sing this song:

I was walking down the street with my dick in my hand,
Shouting "Hey mutha fucka I'm the king of the land"!
I looked up high, and what did I see?
Some mutha fuckin bint sitting laughin at me!
So I turned my cock to 90 degrees,
And I shot that slut clean outta out the trees,
I went round the corner to see what I could see,
A hundred naked ladies just waiting for me,
So I fucked 98 'till my dick went blue,
Then I fingered the clits, of the other two!

This should easily let her know you have a huge dong, some guiys I know have had women drop to their knees and suck you off instantly, so use this wisely.

It may also help if your dressed like a black rapper and if you speak like one (if your already black, i believe this auto pulls in the next nearest hottie for a insta-3some.)

You could also wear one of these t-shirts, that way it states the obvious for her without you having to say a word, or teasingly invites her to ask you a specific question. I hope this all helps.