On the show, presented by Holly Willoughby and Philip Schofield, couples clambered on to a bed to give viewers tips on how to match their sexual positions according to their mood or their needs.
Tracey Cox, a relationships expert, explained positions for couples of different heights or for when they are feeling lethargic.
The act was part of the programme's "sex up your life week", where the broadcasters are showing off a range of ways to revive flagging sex lives.
The couples involved in the raunchy demo were wearing pyjamas as they showed off their moves.
Before the show, Schofield said his co-host was "a bit shocked" at the prospect of broadcasting a slot dedicated to sex.
"Holly just said that was much easier than she thought it would be. You have to talk about these things," the Telegraph quoted him as saying afterwards.
"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,"said Executive producer Karl Newton.
"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 oversexed men to sexual diseases, no area is off limit," he added.