"Hey!" The greeting is very eager and Jean gets up.

Normally he would leap to hug Mikasa, but instead Jean stares at Maru, who's happily snuggling Mikasa. Perhaps even pouting a little bit for all the attention he was getting. Normally he wouldn't be this jealous (just a tiny bit-) but feelings like this were unfortunately amplified.

So he stands there instead, folding his hands over his chest.

"Marco and I were talking that I should try and see if I can control my form. It might make things easier if I can."