Stop talking for a second.
From the ASCII DC3 or XOFF
character (the pronunciation /X-of/ is therefore also used). Control-S
differs from control-O in that the person is asked
to stop talking (perhaps because you are on the phone) but will be allowed
to continue when you're ready to listen to him — as opposed to
control-O, which has more of the meaning of Shut up.
Considered silly.