Shampoo fed up with waiting, makes a deal with R&A. They get married now, have a kid to fulfill the promise between families, then get a divorce and have Ranma come with Shampoo. Ranma says no way, but Akane takes him aside and says this might be an opportunity to get rid of her once and for all. Get married, fake fucking, and get Doc Tofu to tell them that Ranma is infertile (low sperm count or something). Go back to Shampoo and agree to the deal. Shampoo is happy and allows the couple to start making arrangements.
Wedding arrives, Ukyo & Kodachi crash the party but are stopped by Shampoo. R&A are finally married, kiss, and have their reception. At the end of the night they go up to their room, planning on sleeping in separate futons, when Shampoo follows them up. She says that she’s going to make sure they consummate the relationship. Both R&A say no of course, but Shampoo won’t listen to reason, and threatens to take Ranma right now if they renege on their deal. Nervous, the couple enters the bedroom and do the deed with Shampoo watching quietly from a corner. When done, Shampoo asks to see proof that Ranma did indeed cum inside Akane, who, embarrassed beyond belief, but still a little turned on spreads her legs to show the cream pie. Shampoo is satisfied and leaves. Ranma is nervous about actually getting Akane pregnant, but she assures him that she’s on the pill, and has been for a while.
Time goes on and Shampoo watches every night as they fuck, making sure Ranma is indeed cumming inside. R&A are starting to enjoy the voyeur and start going off to places where they might get caught to get the thrill. Shampoo getting frustrated in more than one way about waiting for Akane to get pregnant. Starts to diddle herself while watching, not knowing that R&A are watching her as they fuck.
Time passes and Shampoo is tired of waiting for a positive result. Go to Doc Tofu’s Tofu does his “test” and tells them Ranma has immobile sperm, shows them a microscope with someone else’s sperm (maybe his own?) which isn’t moving much. Astronomical odds that Akane would ever get pregnant. Shampoo pissed since all she wanted Ranma for was breeding stock anyway, goes back to china frustrated in more ways than one.
I’m tempted to do a threeway with Shampoo involved, but wouldn’t know how to write it since I’ve never actually done one.