Rach, Jesse does this too. Lately has been doing it every now and then after he's just drunk his bottle or had a drink of water so i get splattered with milk or water! I dont pay too much attention to it as ive learnt with him if he's squeeling and i tell him to stop he just laughs and thinks its funny. I just take his mind off it with something else. Hopefully theyll just grow out of it but its totally normal.