I now own both sizes of jewelry...i started with the XL (insert size is great) butt found that the jeweled portion (to big) would dig into my butt cheeks after hours of sitting on it (standing or walking is OK) so I decided to get the regular size (insert size to small) the jeweled portion is just about right (a tad larger would be perfect) the stem between the jewel and insert needs to be alittle longer. The regular size being much smaller...I have found trying to adjust the position of the jewel for comfort makes it overly easy to push the jewel inside myself (No, I don't have a big asshole) I think it may be the thickness of my spinkter muscle, if the stem was as long like that of the XL (which fits great in this asspect) the insert would go beyond the thinkness of the muscle and would seat perfect!!