We own both the Share and the Share XL. The Share is definitely more flimsy than the Share XL but my wife and I used it just fine before we purchased the XL. We found getting the base of either Share locked in place in her. After some trial and error we found the best way to keep the Share in place for her was to have her use anal beads in conjunction with the Share. As for me, we just stick with the slow and steady insertion into me. Once it is in we have never had a "too flimsy" issue. And yes, as ScottA suggests, i use my hand to assist with lining up that initial insertion.
Sorry for the delayed response to this post but if anyone has additional questions just send us a note.