Yes most penises are more than 4 inches. The average is 5.5 inches.
When you get aroused the vagina kinda swells to accomdate I mean come on ladies you can get a baby out but I assure you if you go to the bathroom right now and measure it will be significantly smaller.
Let's assume the orignal poster didn't stay aroused for the whole couple of days...
Iud's and ius's are a different matter entirely, firstly they are inserted through the cervix and into the uterus and secondly you are supposed to be able to feel the very fine lines from it to know that it is still in place.