This Morning hosts Holly Willoughby and Phillip Schofield looked on as sex positions were demonstrated on the show.
As the presenters watched, couples - who were wearing pyjamas - clambered on to a bed to show viewers how to put the sparkle back into their relationship.
Relationships expert Tracey Cox gave viewers tips on how to match their sexual positions to their mood or their varying needs.
Prior to the show Phillip said his co-host was "a bit shocked" at the prospect of broadcasting a slot dedicated to sex.
But afterwards he said: "Well, Holly just said that was much easier than she thought it would be. You have to talk about these things."
The stunt was part of the programme's "sex up your life week" which is examining a range of ways to revive flagging sex lives.
The programme has a track record for pioneering items. When it was hosted by Richard Madeley and Judy Finnigan, This Morning used a naked model to show how to check for testicular lumps.
Executive producer Karl Newton said today: "For 21 years sex has been a hot topic for discussion on This Morning and the subject really connects with our viewers who really involve themselves.
"We decided after the success of our love week earlier this year to turn up the heat and launch a special sex week, covering a whole spectrum of issues, from infidelity to poor performance and from over-sexed men to sexual diseases, no area is off limit - and each day our content will be informative, educational and fun."