Howdy, In case you are asking out of genuine curiosity, yes! That can be a real problem for two reasons that immediately come to mind. Firstly, the average vagina is only as deep as the average penis, so a penis that is too long can cause pain durring thrusting for both parties. This is less of an issue with anuses since they do not strictly have an end. There is still such a thing as too deep though, medically. Girth can similarly be an issue since vaginas and anuses are stretchy, but only to a point. Secondly, humans do not have a bone in the penis to help it stay up. They rely almost exclusively on blood pressure. If the penis is too big, it can be very difficult to get an erection, once again making it a problem for all involved sexual parties. Cheers!