Replying...
Intro. You're a 15 year old boy changing clothes in your bedroom when your two 13 year old sisters walk in and see you naked . They didn't mean to catch you naked, but when they see your dick they keep staring at it. They've never seen you naked before, and they've never seen a real dick before either. They are curious and want you to let them examine your dick.

Lisa and Laura

@James