The House knew it had to get the Four into itself, where it was strongest. Where even Emma's powers wouldn't be able to block it. Which was why it was working on increasing their sexual drives and desires, as well as focusing it on each other. For while it's Dunegon Heart was the source of it's powers and reality warping, it was worthless without the mind to guide that power. Due to the nature of it's existence, all four had to synched.
The best bet was during their dreams, convincing them to come to the House the next day by way of erotic dreams. Both Peter and Sue were horny and in a suggestive state, allowing for more influence in their dreams. Or even before. So now Carol and Emma had to be made aroused. While they had variant of hetro and bisexuality, they could be made to focus on Peter before each other. So it cause them to become horny, and focused all three women on the young man.
Carol had a fantasy of being submissive towards Peter, a mix of military culture as well as her father's own views of the genders. Emma, however, was having more dominate fantasies with Peter, both as a school teacher and student as well as dominatrix and submissive. In the back of her mind was the knowledge that in bondage, the sub has all of the control. Peter's fantasies, not only spawning various water facilities, was slowly becoming more dominate with the women. As well, Sue was not only starting to fantazing about MILFs and Cubs with Peter but also a fetish on cheating on Reed with Pete.
The house worked to increase arousal as well add more to their fantasies, which added more to the house...