An art teacher smacked one of his pupils on the bottom with a ruler as he carried out repeated sex attacks on her over a two year period.
James Skelton Smith, 58, admitted sexually assaulting the girl, who was aged between 14 and 17, on several occasions.
Smith, who was a part-time teacher at a secondary school in the Dundee area, has since lost his job.
At Dundee Sheriff Court, he admitted that on a number of occasions between 1 August 2013 and 30 June 2015 he sexually assaulted a child at the school.
He admitted sexually assaulting the girl while she was between 14 and 17 years old by touching her on the body, and on one occasion by striking her on the buttocks with a ruler.
The Crown said Smith was appearing as a first offender but the court was told he had been jailed last year for a series of similar offences spanning several years.
Solicitor Scott Norrie, defending, said: "While he has no previous offences, he was convicted after trial at the end of last year. An eight month sentence was imposed and he was placed on the Sex Offenders Register for ten years.
"That case was perhaps at a more serious level and also involved pupils at the school. Sometime after his release another pupil came forward and this case first called in July this year."
Sheriff Alastair Carmichael deferred sentence until January for reports and ordered Smith - who was not present in court - to appear personally.
Smith, from Dundee, was described as "abhorrent" when he was jailed after being found guilty last year of a series of indecent and sexual assaults against female pupils.
Offences took place over an 11-year period between 2008 and 2019 and the court heard he would regularly drop his pencil in order to crawl under desks in class.
In that case, Sheriff John Rafferty told Smith that the assaults were carried out when he was in "a position of authority and trust."
The sheriff said that Smith targeted a vulnerable pupil and told him: "You sought her out, befriended her, contacted her on social media, and gave her gifts before indecently assaulting her."
On her last day at school he followed her into the street and gave her a "sexual" French kiss, before groping her breast when she returned to hand him work in an empty class.
The sheriff said that Smith had shown "little or no remorse and understanding" of the impact on his victims.
He said: "In my experience, which is considerable, it is not uncommon that persons who come before these courts having committed sexual offences at summary level are often not otherwise inclined to break the law.
"They may choose to offend as you have done for your own abhorrent purposes if they believe they may escape detection and punishment.
"You contrived situations to get down on the floor of the classroom and in some instances crawl under the desks and look up the skirts of schoolgirls. One of the pupils had mental health issues."
