Rothesay man Shanan Rodger begged the 15-year-old to send him a photo of her in a bikini and told her that the image made him ‘horny’.
Rodger, who turned 27 on Tuesday, messaged the girl to say that he could see part of her breast during a swimming trip and that he was “pitching a tent” under his duvet.
Prosecutor Lindy Scaife told Greenock Sheriff Court: “The girl took that to mean that he had an erection.
“She exposed some of this to a school counsellor and then the police became involved.
“The girl was reluctant to speak to the police about it, however, the accused was subsequently arrested and he made admissions regarding the messages.
“His position was that he was ‘just taking the mick’.”
Rodger of Ladeside Place, pleaded guilty to communicating indecently with the child for the purposes of obtaining sexual gratification, or of humiliating, distressing or alarming her.
He committed the offences between August 1 and September 18 last year.
Rodger’s lawyer told the court: “He has lost a great deal through his actions, including his life partner with whom he was with for 10 years, and also his employment.
“His reputation within a small community has all but disintegrated.
“There has been an image of his put around social media with the caption, ‘This is Shanan Rodger, he is a disgusting vile paedo – share so we can all see his face’.”
The solicitor added: “The offences took place during a period of low mood and depressed thoughts.
“He fully accepts responsibility for his behaviour.”
The court heard that Rodger was of ‘moderate risk’ of re-offending.
Speaking in court, Sheriff Andrew McIntyre told him: “It is important that children are protected from all forms of such activity.
“It is important to ensure that any risk you pose is addressed to the greatest possible extent.”
As well as being placed on the register, Rodger will also be under supervision for three years and must complete 160 hours of unpaid work within nine months.
He is to have no unsupervised contact with any child under the age of 16 and must make any internet-enabled device available for inspection and not download any software which can erase his browsing history.