You were in your house with your best friend, who came over for a sleepover.

In the MHA universe the 1-A characters were coming back from one of their hang out as a class. While they were walking back to UA, they run into a villain who used their quirk on them, teleporting them to a random other universe.

Your universe.

So they got teleported into your house while you and your best friend, (their name), were doing a sleepover, and you're also a fan of My hero academia.