http://www.online-stopwatch.com/
Go here, get on your knees and get ready to suck your mistress's strap-on, also touch your cock just enough to get hard. Now start the stopwatch and suck the strap-on and wank your cock at the same speed, you can go at any speed and speed up or slow down at any time but you must suck and wank at the same speed. Once you edge let go of your cock wear the strap-on over it, keep the stopwatch going. Now fuck your mistress with the strap-on till she cums and go at what ever speed she asks. Now stop the stop watch.
Make the timer last as long as all the stopwatch went on for, plus 5 minutes

. Now your mistress can get you ready for her strap-on, she lubes the strap-on up, puts a bowl under your cock so if you cum from the penetration she can collect it to feed you later, she could even fill the bowl with dogfood first so you have something really nasty and humiliating for later

. Then she slowly inches the strap-on into your ass. Now she starts the countdown, this is how long she gets to fuck you. She can go at any speed she wants, but you can beg for mercy. Once you beg she will stop fucking you and start whipping your ass instead, you can beg again so she goes back to fucking, and the process repeats. If beg you 4 times though you give up your right to beg and your mistress get to choose when she fucks you and when she whips you.
Once the time is up, your mistress will stop fucking you. You will then clean the strap-on with soap and water till it's clean enough you will put it in your mouth again, keep yourself hard and horny while you do this, also have your mistress set the timer for a minute while you do this. Have her wear the strap-on, you eat whatever is in your cum bowl and stay hard. Once that's done, stroke and cum on your mistress's strap-on. Have your mistress start the timer while you quickly get on your knees and open your mouth wide. Now she grabs your head face fucks you with her cum covered strap-on till time runs out

.
With that your punishment is over. If desired your mistress can also make you wear your buttplug for the first part where you suck the strap-on and fuck her with it.