An idea for the next gen Victini could be to have her want to lose to win and if she wins she loses long term. Since she can make an almost unlimited energy so tiring her out would not work in battle but since she is a fire type the MC could some how build up her sexual heat to a point where she would want to stop fighting thus lose and have sex and realize its better than having victory herself.
Another event that can happen is when the first children are ready to be sent to Maple the transportation vehicle that comes has an unexpected passenger that really wants to meet the MC again. It would be Pikachu that has been waiting for the MC and saw that Maple showed a picture to the piolet and thought they were going to him. So this would be a short scene that the MC has the option to have sex with Pikachu before sending her back to maple again with the other legendary Pokémon children.