AFAIC It depends on whether he has experimented with 'self penetration' or not. If he has extended his self explorational activities from traditional masturbation to exploration with his fingers in the bathtub maybe via the handles of hairbrushes, even bottle tops ...or possibly the surreptitious ordering of small/medium size dildos on ebay somehow, then maybe 12-16 depending on his resourcefulness, sex drive and rectal sensitivity. Just out of curiosity, why do you ask? ;-) Fizzzzzzzzzzzzzzz |