A man told a 13-year-old girl he wanted to have sex with her in front of her younger brother, a court heard.
Limmick Gabbitas, 20, outlined his fantasy in a series of messages to his victim on WhatsApp, Facebook and Snapchat.
Norwich Crown Court heard that he was caught after police became aware of his correspondence with the teenager, who cannot be identified for legal reasons, and raided his home in Cringleford, seizing his devices.
Danielle O'Donovan, prosecuting, said that as well as online chats about him wanting to have sex with her in front of her brother, police also found images of the victim performing sexual acts.
Gabbitas appeared at court for sentencing on Friday (October 13) having admitted three offences relating to the girl: sexual activity with a child and two counts of inciting a child to engage in sexual activity.
He also admitted to three possession of indecent images offences relating to the victim, including 15 of category A which are serious.
The defendant, who now lives in Nottinghamshire, also admitted four other offences including decoys - not actual victims - one of whom purported to be a 12-year-old girl and the other a 13-year-old.
Imposing an extended eight-and-a-half year sentence, made up of four-and-a-half in custody and four years extended licence, Judge Alice Robinson said Gabbitas had "entrenched unhealthy sexual thinking and behaviour".
She did however note he had suffered "appalling trauma" as a child.
Michael Clare, mitigating, accepted "this was very serious offending".
But he said the defendant was a "damaged, lonely, immature 20-year-old" adding "this is a naive, socially-inept, lonely boy".
Mr Clare said he deserved credit for his pleas and ought not to be considered a dangerous offender.
He said his life "started in difficulty and got worse".
Gabbitas was also put on the sex offenders register for life.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules hereComments are closed on this article