Sheffield Crown Court heard how Mark Butterworth, aged 28, was found guilty after a trial of 19 counts of sexual abuse against two youngsters when he was a teenager and the boy complainant was aged between seven and 12 years old and the girl complainant was aged between eight and nine years old.
Judge Rachael Harrison told Butterworth: “I bear in mind your age at the time of your offending and the information I have read about you in the psychological report about your limited IQ.
“You would have been immature and at times a child yourself but there is a significant disparity in age between you and your victims.
“You used access to your computer games as a bribe to get them to behave as you wanted. In my judgement you used grooming behaviour with each of them.”
Judge Harrison described the offences committed against the complainants who were just young children and cannot be identified as a “campaign of sexual assault”.
A jury found Butterworth, of Lilac Crescent, Hoyland, Barnsley, guilty of 13 counts of sexual activity against the boy.
They also found Butterworth guilty of six sexual offences against the girl including matters involving an indecent image, making her watch pornography, and sexual activity.
The boy stated he has tried to block out what happened and move on with his life and he has been reassured by his family that he should never blame himself.
Also, the mother of the girl stated she has really struggled emotionally and she self-harms and finds it difficult to talk about her emotions.
Richard Canning, defending, said Butterworth had committed offences when he was under 18 and when he had only just become an adult.
Judge Harrison said: “His intelligence is limited and he suffers from - and has done for some time - depression and anxiety.”
She sentenced Butterworth on April 29 to 12-and-half years of custody and he was also made subject to the Sex Offenders Register and a Sexual Harm Prevention Order.