Go for your sister, Nicoline, and invite her out

You take a deep breathe, "I think it would be easiest if we impregnated my sister, Nicoline." There is a bad after taste in your mouth after saying that but you do believe it to be true. Two random girls in a day would be too much but your sister was already here.

Jessie nods his head solemnly, "alright, if we must."

After some thought the two of you decide best course of action is to actually go swimming and invite your sister out to join you. After all it was something the two of you would have been doing today any way.

You swap swim suits, Jessie puts the swim trunks on easily, of course you struggle a bit with the string bikini Jessie had brought. It is not exactly hard to put on but tying the bows on so they are tight, yet not too tight, also to not look like a mess is where you have trouble. The top gives you the most difficulty agin and Jessie offers to help.

"No, last time you helped me I ended up with a pussy full of cum," you say while fumbling with the strings.

"Come on, that is hardly fair," Jessie frowns and steps forward.

"I got it," you say ignoring Jessie's comment and twirling to show the cutely tied bow on the bikini. It unexpectedly makes you feel happy and warm all over wearing the revealing outfit for Jessie.

Jessie stops and stares, maybe feeling the same thing, "you look good."

You give him a quick peck on the lips, "you think so?"

Nodding, "defiantly, now let's go get your sister."

You let out a sigh as Jessie reminds you of what you two will have to do, "right."

You step out into the hall and knock on Nicoline's door, "Niki? We are going to the pool would you mind joining us?"

You hear some scuttling around in her room before she opens the door. She looks a bit perturbed until she sees Jessie. Her eyes light up and she drops her jaw for just a moment while she stares at his toned body, standing in the swim trunks. "Um, sure I will join you. Will be out in a few minutes."

"Great, see you soon," Jessie says, Niki blushes and shuts the door.

Minutes later you and Jessie are already swimming around in the pool discussing what you might have to do next when Niki arrives. She wears a more modest one piece you are not surprised by. Your sister is not known for showing off much skin.

She greets you both and her eyes linger on Jessie for a moment before she jumps in. She then asks, "by the way how did you know my name? Did my brother tell you or something?"

"Oh yes," replies Jessie enthusiastically. "He speaks very highly of you," Niki beams at him. While not technically a lie, you do admire your sister, the way Jessie rolled it out was remarkable. Having all the knowledge of a girl in the body of a boy gave him an unfair advantage.

"Speaking of which, where is he?" asks Niki.

You glance in Jessie' direction, "that is a good point. Why don't you go call him Jessie? I will go with you and bring us all out some drinks."

"Oh, sure that sounds like a good idea," says Jessie as he swims to the edge of the pool to get out. Once back inside the two of you, 'pretend' to call yourself. While also getting drinks but more importantly ironing out the rest of the plan.