Noodle leg refers to a "noodle" in the swimming pool, where you would put it between your legs, like a penis. A penis with very long length but very minimal girth.
Also refers to a long needle dick, thin dick, pencil dick, wire dick etc.
yo baby tyrone, you got a noodle leg man, are you lacking girth dawg?
With the noodle leg! (Do it, do it, do it!)
Now do the noodle legs! (Snap!)
Now do the noodle legs! (Yeah!)
Now can you give me seizures while I'm bustin' a nut?"
(I love tha pussy - Alpa Chino)
After you have sex, you are done so good that you try to walk and your legs are untrustworthy. Your legs buckle and fail to hold up your body, or at least it feels that way.
Baby, I had noodle legs so bad I had to crawl to the bathroom.
That girl did me so good, I had noodle legs all night.