The court heard Marsden was living at his family home in Wigan with his wife and young children at the time of his offence in February 2023.
The Cheshire Constabulary civilian supervisor was working in the North West Motorway Unit in Newton-le-Willows.
Martyn Walsh, prosecuting, said Marsden had logged into his Twitter account at work when he was talking with the undercover officer, and took a photo of himself in his boxer shorts.
Mr Walsh said Marsden had described the “girl” as “sexy” and made requests of her using sexualised language.
He told her: “I don’t mind some risk.”
After the online chat police arrested Marsden at home.
Steven Nikolich, defending, said Marsden had no previous convictions and was “someone probation can work with”, creating a realistic prospect of rehabilitation.
His ex-wife wrote a letter to the court on his behalf.
Judge Anil Murray ordered Marsden to carry out 150 hours of unpaid work and to be on the Sex Offenders’ Register for 10 years.
