@Yaoi Whispers now this is a better explanation, do y'all remember when they first met, guessing was the first one to hold onto dojin when he went into heat for the first time, but after that dojin started having feelings for him and then when he was out of his mind and knotted with hyesung, that's how the baby came about, so I don't really think any of them were forced, I think it was love at first sight or they can't get enough of each other 
