NAME_1 and his friends NAME_2 and NAME_3 talk NAME_1's younger sister NAME_4 into cosplaying a sexy maid outfit for them.
They boss her into different steamy situations and take many photos of her sexy young body. NAME_1 blindfolds NAME_4 and explains to the group that her body is off limits, except her mouth.
Flesh out the story and continue, make it smutty and lengthy, at least 20 paragraphs. The most exciting thing is the taboo.