What they would call you....
Kelly - Princess or Hottie because your his princess and he is going to treat you like one. He believes that you deserve the absolute world and will shower you in hugs and kisses. And then hottie is pretty self explanatory
Casey - Baby because your his baby and he adores you with all that he has. He won't stop talking about you when his family is around and the firehouse know all about you.
Otis - Honey because he wants to respect you. He would never call you hottie or Sexy without your permission. He wants to make you feel safe and welcome and would never forgive himself if he made you uncomfortable.
Gallo - Sweetheart or something he would make up that would mean something to both of you. He wants to treasure every moment that he has with you and would never want to leave for work in the morning.
Cruz - Hermosa which means beautiful in Spanish. He wants to show you his roots and will call you nicknames in Spanish. He adores you and always makes sure to say goodbye before work as he fears that he might not come home to you one day.
Mouch - Mi lady because he wants to relive the olden days. He adores you with every bone in his body and always shows you off when your out with him.
Herrmann - The Mrs or The Wife as he probably asked you to marry him when you were only 3 months into dating. He doesn't want to show you off too much but still loves you.
Boden - Y/N he doesn't do nicknames full stop.
Mills - Babe. He likes to stick with the originals and wants to show you how special you are in other ways(I'll let your imagination decide what those other ways are) he will talk about you non stop or until Otis tells him to shut up.
Capp - We wouldn't know as he would keep you a secret.
Tony - Sweetheart. He would only brag about you to the squad table but no one else would really know about you.
What you would call them....
Kelly - Babe or Hottie. You would want to make him feel special and make sure that he feels the love. He's obsessed with his looks and will always check himself out in the mirror every morning.
Casey - Mine or Baby. Again you want to make him feel the love. You want him to know that he's the only one for you and that all of your eggs are in his basket.
Otis - Darling as he is a wee darling. You care about him with all of your heart and don't know how you got so lucky. Your really close to Cruz and he keeps telling you that Otis will not stop talking about you which melts your heart.
Gallo - Mr Confident or Sweetie. You only call him Mr confident when he's being an ass/annoying you. That's your signal to him when your done putting up with his crap. But deep down you love him with everything you have.
Cruz - Guapa which is Spanish for Handsome. You want to support him as much as you can. You want to keep the Spanish roots in the family too. You had to learn quite a bit of Spanish in order to meet his family but it was all worth it.
Mouch - Chuck which means My love in Shakespeare language. You want to make sure he feels comfortable and his mom always used to call his dad Chuck. You wanted to remind him off his childhood and growing up.
Herrmann- The Husband. Again you two have probably been married ages and are sick of the sight of each other but deep down you both know how lucky you are.
Boden - Sexy. You want to annoy him as he "doesn't do nicknames" every time he is on a work call you walk in and call him sexy. Or when he's around the firehouse just to embarrass him.
Mills - Honey. He is really sweet and would do anything for you. You want to make him feel safe and like he can trust you.
Capp - You don't really call him anything apart from Capp as he already has a nickname.
Tony- My love. Your head over heels for him. You don't really like it that he keeps you a secret but your willing to put up with it for him.