both the boys slid their shirt off.
"did it work?" Alan said.
"i think so... ahhh!"
Jon and Alan's lower halves both changed to fit their diguises. Jon's left hand also changed into a more femmine version due to a bracelet he was wearing.
"Oh... crap." said Alan, (or Alison, now) sliding his hand down his pants ot discover that his penis was gone, now replaced by its female counterpart.
Jon (Joy) said, "crap. now we're half girls. what are we going to do?"