powel

At the moment I can insert a coke-can easily without any pain or issues, but any size above that starts to put pressure on my tailbone(will eventually hurt when I sit too long or get up from chairs). I know that people with bigger body structure can go bigger in size, but I have seen tiny guys like me being able to insert almost a 1.5 liter coke bottles!! Is there a way to get around this or am I stuck like this forever???