Fingering a girl makes you susceptible to various diseases like rashes that burst into open sores. It can also lead to leprosy. 50/50 chance of that. That's because fingering is a sin according to Leviticus 15:30-31 "Thou shalt not puteth the finger beneath the loins of a maiden or thou shalt suffer abominable disease upon the skin for the loins of the maiden are unclean."