Swimsuit, bikini, underwear, dress, whatever works. Just as long as they're made naked in some water.
Bonus points for being submerged.
Not in a bath, not in the raid, only pools, water slides, or ocean/lakes/ect.
Nice thread
>>1953514
OP here, part 1 to this
>>1954618 If anyone wants to see the full ero-manga go here http://www.mangahere.co/manga/mahou_shoujo_neko_x/v01/c001/ it has 2 volumes and this is a side story