Certain dialect derived from San Jose, and spoken throughout the Bay Area as a type of slang used as substitutions for incriminating words and statements. Used as a type of code language to ensure there's no ear hustlin' going on in the near vicinity.
When an extremely obese person's thigh fat is so out of hand that it appears to engulf the knee, bypass the shin and calf and ends up stopping at the ankles. Combination of "thigh" and "ankles".
Brett: Hey, Did you see that woman standing in the buffet line?