To use the bathroom

Erza/Juvia felt a familiar sensation in her behind. She knew that she really had to poop. The pressure was building on her abdomen as she visibly groped her new buttocks to keep it inside.

'I can't believe that Juvia's body needs to take a crap. ' Erza/Juvia thought.

Realizing that she couldn't handle the pressure, Erza/Juvia desperately hobbled over to the women's restroom of Fairy Tail. Much to her embarrassment, she was audibly farting the entire way. Fortunately, the sounds of the Guild's revelry drowned it out. However, her bathroom visit was interrupted by...