Everyone does a little striptease.

Everyone is in their underpants, the idea being to wait until one is about to jump in the boiling water before completely disrobing. Sophia is the only one who's lagging behind, still wearing her pants and bottom-layer shirt. Emma decides to take the lead and encourage her. Sliding open the back door to the house and letting the cold air surge in, your girlfriend struts out to the hot tub, and with a flourish, doffs her bra and panties. She gives the slightest wiggle of her ass before hopping in, letting the water envelop her breasts just past the nipple. Your parents follow, one by one, then hers. Your Mom rubs her jugs together and does a little spinaround. Not to be outdone, Emma's Mom gives her own ass a little spank for the onlookers. Emma gives a playful clap as your Dad pulls down his boxers, and when Emma's Dad makes his way over, he gets a full ovation from the three ladies already in the tub. Everyone's getting in the free spirit of things, and the bubbling water means the men no longer need to worry about hiding their erections. You strut on out, master of your fortress, king of the castle, and Emma gives a subtle arch of her eyebrows, letting you know you're still her absolute favorite.

Now it's just Sophia who's left behind. She's standing just in view by the back door, and there's still one space left open in the tub for her, but she's still just too skittish to come out.