anime thats manly about body swap or gender change

Kokoro Connect

The main character in Gonna Be The Twin-Tail gender swaps when he goes into combat mode. Not sure how much of that theme they'll explore if he isn't swapped while off the battlefield. Only a couple episodes are out so far.

Fairy Tail

in Fairy Tail anime there was one episode a magic which changed everyone's gender........he he eh
in this pic both Lucy and Gray both swaped their bodies......eh eh eh
later it happened in entire guild...........eh he he he
in this pic Gray inside lucy trying to remove lucy's shirt and lucy inside gray trying to stop him.........eh eh eheh

Birdy the Mighty Decode

Kashimashi Girl Meets Girl

Wouldn't Ouran High School Host Club be one? idk i haven't seen it.

Himegoto- link

And if you're looking for something more serious,

Hourou Musuko- link