First they joke about not liking femboys but thinking they are cute, then they get curious and look at them feeling attraction to the femboys, they still think they are straight and that femboys are girls with dicks, but soon enough they're watching sissy porn and jerking to them. They start thinking that maybe taking it up the ass feels better than jerking. They start doing butt stuff with dildos and find that's it's the best way to get off. Soon they notice the femininity in some of their features and want them to be more like that of femboys they see, they cosplay anime girls a few times then realize they are attracted to themselves in this state. They end up becoming the femboy and posting pictures so people tell them how cute they are which feeds their ego and continues the cycle. It all starts with Pantsahat's videos This is the femboy pipeline