I ordered a vibrating flesh-light type toy from China on Alibaba and I can hardly fit my (average sized) dick in it. I have to push the head hard into it and eventually it pops in. It's hard to not cum in a couple of minutes. Made a sex toy ages ago out of a vacuum and other household stuff. It had holes on the side that you could play like a flute to change the suction. That thing was pretty cool. Every now and then I think about trying to patent it... but knowing my luck it'll rip somebody's dick off and I'll go bankrupt or end up in jail.