You say nothing except "mrgh" through the gag

Seems like she was expecting a protest but since it didn't come she pulled the marker and second clamp. She adjusted clamp so that the two pointy ends were digging into your flesh, and moved it around until it was centre and horizontally adjusted, before releasing it and marking the points with a marker.

Putting down one clamp (While the second one was still holding your nipple erect) she took a long needle and a cork into her hand and presented them to you as if intentionally intending to instil fear in you.

Task at which she succeeded quite well. Unfortunately it was to late to change your mind, and the leather straps made sure of that.

She put the cork on one side, needle on the other, adjusted the clamp, then without a warning...