James: When you and him do pranks together and when you are determined to win during quidditch.

Sirius: When you are confident and stand up for yourself when people are being rude or awful to you.

Remus: When you snuggle into his neck, whispering about how much you love him.

Peter: When you defend him (especially in a duel)

Regulus: When you train together in quidditch and he sees how skilful and passionate about it.

Lily: When you are as passionate about something as she is.

Marlene: When you are competitive, especially against her because she finds your confidence and determination hot.