Wow! Lots of things that I like here.

First, Emily's curiosity. I like how she tested the crushing on Mark, so now she knows her limits and can punish him confidently without feeling bad if she broke his bones or soemthing.

Second, Mark's arguement failed against Emily, so she has no reason not to play with Mark. She can do as she pleases.

Third, I like Emily's creativity using dental floss. Tying up his legs and connecting them to her finger gives Emily control and she then knows his location. Also, I look forward to when she ties him up to other places as well.

Now that they understand each other, I cant wait to see what happens in the next chapter!