In the fold where the scrotum meets the inner thigh lies a secure place to put contraband (drugs, money, ID, etc...). Similar to a wallet/billfold the scrotum and inner thigh hold items snugly due to the fold or crease.
Can I use your bathroom quick, I need to grab somethin' outta my ballfold.
Damn, did you see how dude was walking; definitely put too much in his ballfold.
Hey, did you have this in your ballfold? It reeks like balls!