Couldnt find a flair tag, nsfw.

Need some help to size the bar for my ampallang. I was pierced at an 8g and it is healing nicely now. I tried to put in the shorter bar the piercer gave me but when I'm soft it doesn't come out the other side at all. I can compress just a little and it would technically fit. The problem is that I am a grower. Not exactly monster sized by any means but the head does grow when erect. How would I go about finding a proper fitting bar with out buying 3-5 different bar sizes and trying them. Would taking a picture with the longer bar and fully erect help a piercer narrow down the size better? Or would there be a better method to helping the piercer size a bar?