You, James and Regulus were sat in James' dorm, James and Regulus were kissing, while Regulus sat on James' lap, James reading.

Regulus: "oi, my brother is here! distract him-"

Sirius walks over to the three

Sirius: "wait, reggie?"

you suddenly get up, going over to sirius, wrapping a hand around his neck and kissing him, attempting to distract him