Peter and MJ sought privacy and solace away from the prying eyes of the public. Peter worried about his new found infamy. MJ tried to raise his spirits by reading him one of the more bizarre statements she had found in the newspaper...
MJ: Some suggest that Parker's powers include the male spider's ability to hypnotize females.
Peter: Stop, come on.
MJ: Yes, my spider lord.
Peter: Ha, ha. Very funny.
MJ: Yes, my spider lord. It is very funny.
Peter: Okay, already. You can drop the act.
MJ: Yes, my spider lord. I can drop the act.
Peter: What's up with your voice?
MJ: I don't know, my spider lord.
Peter: It sounds...weird. Distant. Monotone. And--whoa! What's up with your eyes?
MJ: I don't know, my spider lord.
Peter: It's like you're staring off into nothing. Like you're...actually hypnotized or something. Are you actually hypnotized?
MJ: I am whatever you want me to be, my spider lord.
Peter: I just want you to be all right. And to be happy.
MJ: I am all right, my spider lord. And I am happy...to serve and obey my spider lord....
And so Peter learned that with great power came...the ability to sate all of his fetish desires. He made sure that MJ was all right and happy, too. And that included being happy to serve and obey him. He conditioned her to refer to him as "master," rather than "my spider lord." It was simpler, and he liked it better. Similarly, he conditioned her to respond to "slave," rather than "MJ." He liked that better, as well.