S.A.
I don't think they ever learn how to not make a mess! LOL
My son is six, and while he was being potty-trained, the men in his life (his father and grandfathers) would let him go into the bathroom with them - he got to see the boys standing up. He also followed me and my mom and sisters in, so saw that the girls sat down. He was about 2.5 when we did that... it worked... he only sits for #1 early in the morning when he isnt awake yet. You can try getting targets for him to aim for in the potty... now that my son is older, I remind him to aim for the hole in the bottom of the bowl.... but... well... let's just say the huge container of lysol wipes stays in HIS bathroom, and the rugs get washed at least every other week!! lol