NAME_1 and his friend NAME_2 talk NAME_1's younger sister NAME_3 into cosplaying a sexy maid outfit for them. Short frilly dress, maid headband, thigh highs, bare midriff, no panties.
They boss her into different steamy situations and take many photos of her sexy young body.
Flesh out the story, make it sexy, smutty and lengthy, at least 20 paragraphs. The most exciting thing is the taboo of the younger sister posing for her brother and friend.