The real-life usage of Egon's Law is applied when two or more men are urinating next to each other, perhaps in a community trough or a row of bushes. If anyone crosses their urine streams, those two have violated Egon's Law (don't cross streams!) and are therefore automatically gay.
Whoa whoa watch it pal! Don't violate Egon's Law! I don't want to be gay with you!