I have thought about it, but have problems with the logistics! As others have mentioned, it is extremely soft, which leads to how do you get it in? My only idea was to turn it solid by giving it a shot of liquid nitrogen. So it is now firm enough for insertion, but is -132 degrees cold,,,,not something my wife would go for.
So we get it inserted and are ready for penetration. Did I mention cold? We all know what happens when certain parts of the male anatomy gets cold!
So assuming penetration does occur, I seriously doubt the sensations would be anywhere as great as without the fleshlight or as great with the fleshlight alone.
Well,,,good idea anyway