In How I Met Your Mother, we all remember that Barney and Ted made a bet for a belt to see who will able to do a threesome first. So when Ted's wedding day (not the actual but with Stella which was cancelled eventually).
So barney had an urge that he did not want to do intercourse as he was waiting for Robin but someone (I don't remember who!) was hitting on him. Then Robin knocks his room and seeing inside left in disgust, so everyone thought that would have been the girl hitting on him, but just 10 seconds after the same girl arrives and looks inside, we all thought the girl will also leave but she went inside (I am assuming that what Robin saw was another girl). So would not this be counted as a threesome? Then I thought the TV show makers must have forgotten the bet.
Eventually, they made an episode in which Ted again met Tory (I am not good with names, so I may be wrong) or the pineapple girl (when Ted had forgotten what happened last night), so eventually, in that episode, Ted was close to having threesome and Barney was scared to hell that he will lose the bet. Was this some mistake by TV show makers?