I used to do full insertions all the time, until I accidentally lost one of these that DIDN'T have a chain on it.
http://www.edenfantasys.com/dildos/classic-dildos-and-dongs/colt-thrusterI was sitting on the floor, grinding hard with it fully inserted in my ass, when it suddenly slipped in. Thanks to my internal curves, it got sucked in a few inches and the flat bottom end got lodged against my tailbone. All attempts by both me and my wife to extract it failed, and resulted in blood. That led to the emergency room to have it removed, and a stay in the hospital until they were sure I didn't have any infection or permanent damage. It was embarrassing, but lucky for me, the ER tech on duty that night was a gay guy who understood my problem completely, and he and the hospital staff did a great job of keeping things as private as they could; I think they actually listed it as an "intestinal obstruction" or something similarly mundane.
From that experience, I learned a lesson: never put in what might not come back out. Now, all my toys have to have balls or a base of some kind to keep them from going all the way in, or simply be too big to fully insert. I never use hard objects with flat ends like cans or glasses. I do sometimes still do full insertions with double-ended dildos, but those are flexible and have rounded heads instead of flat ends, so they come back out easily.
Safety tips learned the hard way. Please learn from my example.
