Just to clear things up!
You= (On His Phone)
Him= (On Your Phone)
Master Splinter
You- Darling
Him- Sweetheart
Leonardo
You- Love
Him- Leader
Raphael
You- Chika
Him- Tough Red
Donatello
You- Sweetie
Him- My Nerd
Michelangelo
You- Baby Cakes
Him- Honey Bun
Casey Jones
You- Hot Mess
Him- Cold Hearted
April O'Neil
You- (Your Hair Color)
Her- Reddie