May you not fall in with a black-bottomed man

Explanation

that is, may you not fall in with some manful and mighty fellow. The proverb is from this. Theia, daughter of Oceanus, had two sons; these used to wrong all who passed by. Their mother warned them to do no wrong, lest, falling in with some "black-rumped" man, they pay the penalty. Heracles came upon them, and binding their feet together to one another, hung them down from his lion-skin and slung them on his shoulders. They, seeing the hairiness about Heracles' rump, laughed, remembering their mother. Heracles, asking the cause of their laughter, was pleased, and let them go.