You ask Sara if she gave Alex "permission" to hook up with you

"Well," you say to Sara, "what did you tell Alex?"

Sara gives you a naughty look. "I told Alex," she says, "that you'd be a great teacher. And she should go for it."

"And do *I* have your permission," you ask, giving Sara a mischievous glance of your own, "to run my hands up your little sister's sides, to tease her, to push my fingers inside her underwear and tease her clit, and finally to push my hard cock into her tight body again and again until I feel her come around me?"

Sara's whole body shivers with what can only be lust.

"You, sir," Sara says, "Have more than my permission to fuck my sister at the wedding. Teach her. I want you to enjoy her body. Help her learn to enjoy her body. She deserves it."

You both sip from your beers. "In fact," Sara says, "I have to admit it's kind of hot."

"Which part?" you ask.

"Having siblings," she says. "God that's hot. I would have loved to have fucked you and your sister."

Your eyes get wide. You had always suspected that Sara was attracted to both men and women, but you never had confirmation until now. "Well, my sister is my plus-one," you say. "But since you won't have much opportunity to bed her before your wedding, I guess you'll just have to live through me."

"Mmmm," Sara says. "Cheers to that."

Your drinks clink together.

"So," Sara says, "would you like me to give you guys an excuse to be alone together at the rehearsal dinner?"