We did something similar in the Marines.  Whaling  *I never fully participated due to strictures you'll see. * They'd put $20-$100 down as the pot (depending on how broke they were) , then go out and find the biggest nastiest whale they could find,  sleep with her, and acquire some proof. Normally bedsheet sized panties or photo/video. I never participated cause the dirty animals would actually fuck the fats, but I'd wing man or act as verification aaaaaand participate in judging.