Ive heard of drikin ur pee before. My dad when i was lil had a sickness and the doctor recomended him to drink his own pee so he did for a month and he got better.
I guess its to double filter the pee to make sure ur body is gettin as many proteins and amino acids it can get.
All that "nasty" stuff Marquez has done can also give him a small psycological advantage over Mayweather, knowin Mayweather isnt drinkin his own pee instead his gettin his nails done.