Lewis Morrison, 29, had downed six or seven pints when he started behaving like Jack Whitehall in the BBC sitcom Bad Education.
Referring to female pupils at his school, the music and drama teacher said: “Lads, you need to go where this lot are for the after-party, they are gagging for it.”
Mr Morrison, who had already handed in his notice at Albion Academy, Salford, was also shouting and swearing.
Then he made a headbutt action and said he would knock out the school principal, adding: “Put that on Snapchat”.
Mobile phone footage of his behaviour was shared widely on social media, a disciplinary panel heard.
One witness said Mr Morrison, who had taught at the school for four years, was “sloshing around his pint and swaggering”.
A second witness said pupils had commented that he was drunk, to which he responded that he did not care as he was leaving.
The panel, sitting in Coventry, heard that the teacher was asked to leave the Year 11 prom at Hotel Football near Manchester United’s Old Trafford stadium in June last year.
In a written statement, Mr Morrison said: “I was not falling over, fighting or being sick… admittedly I had a few too many drinks.”
He denied encouraging sexual activity among pupils and claimed his comments had been twisted and taken out of context.
Panel chair Dr Melvyn Kershaw said: “Mr Mor-rison’s actions were those of crass stupidity, which represented a considerable misjudgment as to what was an appropriate amount to drink, and language to use, at an end of year prom.”
The panel decided not to ban him from teaching as the incident was a one-off.