I love wetting my nappies in any position I have to say tho laying on my tummy is pwobly my favorit because then all the wee goes to the front of the nappy and causes it to swell up in the front which is I really like
also depending how full my nappy already is ill pee in different positions to try to manipulate where it will go
and yea sometimes its really tough to wet like laying down or sitting so I just stop trying and eventually when u have to go bad enough you will be able to push it out