When I do bottom, I can take a much bigger cock than a dildo. A cock can mould itself a little (even a very hard cock) to my ring and gently push through, whereas a dildo is hard and unforgiving. Don't get me wrong, I love my toys, but a cock of the same size as a dildo slides in much easier. This is why I will open up my 'boy' with a good sized dildo before sliding my cock into him. If he takes the dildo, he is really going to enjoy my cock.