Negima inflation idea

I have an idea for a Negima themed inflation artwork. Any and all artists familiar with the series, this goes to you. Now in the manga/anime, there are three characters who are cheerleaders:
-Sakurako Shina
-Kakizaki Misa
-Madoka Kugimiya

(Along with inflation, I have a cheerleader fetish)

The idea I have going is that one of the three is being inflated (or all three if the artist chooses) as part of a routine. The first idea is one is being inflated by another as the third watches on. The means of inflation is a helium tank inserted via the mouth or bellybutton. I think that a semi spherical shape, but with the inflatee’s arms and legs cone shaped would work, but I’ll leave it up to the artist. The second idea has all three inflated, but the same shapes apply.