Mistress sets screw on speculum and says you're doing fine.
You may now touch your cock and massage it until it's hard.
You may not cum without my permission.
You must keep something in your ass for the remainder of this tease.
Once your cock is hard, you may work it to the edge, while manipulating your asshole and then you may continue . . . but, of course, you will have no relief at this time and may not cum.