Eren:
Eren would get all giddy like a little puppy and he'd hug you and thank you so many times.
Levi:
Levi would genuinely smile and give you a long passionate kiss.
Armin:
Armin would get all flustered and nervous and promise to surprise you as well all while being adorable.
Jean:
Jean would kiss the top of your head and force you to share the surprise with him because love.
Marco:
Marco would continously thank you while smiling really big and giving you nice little kissss.
Erwin:
Erwin wouldn't really say much, he'd probably say thank you once and sweep you into a kiss.
Hanji:
Hanji would have a major freak out and thank you a gazillion times and then forget anyone else exists.
Mikasa:
Mikasa would simply say she loves it and hug you tightly.