I can see why boys like them.

Anthony and others at the pool party suddenly changed gender. To put it simply the girls came boys, and the boys came girls. When the boys changed into girls their swimsuits transformed into either into one piece swimsuit or a bikini, as the boys' swimsuits changed so did their body became more, like girls.

And the girls' swimsuits and bikinis turned into male swimsuits or swim trunks. And their feminine bodies became boyish like regular teenagers.
It shoulder shock them, but it didn't they were curious and a bit excited, Emma secretly a wirily smile. That Anthony and newly transformed girls was willing give the newly transformed boys BJ's. And they were willing to do it.
After a few hours, and a couple of more BJs and kissing. Anthony was ready to leave the party. He tried and tried to put on, this own shirt and pants on.
As he slowly tried to put on his shirt on it felt a little tight. And his pants, he couldn't get them over his now feminine hips. They were too tight in the hips, to lose in the waist.
Emma and the other transformed girls and boys thought it was funny. That Anthony had a hard time to put on a simple pair pants and shirt. So, the newly transformed, Emma gave Anthony, her own shirt and pants to Anthony. And gave him or her a kiss.
And said that you can tried a dozen times. Either you'll ripped them, or you'll hurt yourself.
Anthony was a bit stunned; she was started accepting her new feminine body.