The switch resulted in improved and more composed performances from the former Kettering man.
He told BBC Radio Cambridgeshire: "I feel more comfortable in the midfield because there's less pressure. You get more time to take a few more risks."
He added: "At the back it's more intense and you have to be on the ball all the time.
"Sometimes it's hard to make the adjustment mentally because you want to take a touch and it's not on at the back."
Geohaghon's midfield appearances under Gannon uncovered his ability to play long, accurate passes and he is happy to be finally showcasing his previously hidden skill.
"It's something I've got in the locker," he said.
"When you've got the ability to get it down in the middle of the park and have that extra touch to make the passes it's even better."
New boss Gary Johnson's first game in charge saw Geohaghon revert to a defensive role in the 2-1 defeat to Leicester and he admits he will have to wait to see where he fits into the new regime.
"I'm not too sure how the gaffer's going to go into this new system," he said.
"But I'll obviously see where he wants to play me and we'll take it from there."
The former West Brom youngster has endured a frustrating season for Posh, in which the club were relegated with four games still to play.
But they have rarely been embarrassed, having lost by only one goal on 17 occasions, and Geohaghon thinks the team need to show their quality.
"Knowledge cannot be facilitated unless it is acted upon. If the boys are not acting upon the knowledge and the potential they've got then we're not going to get anywhere.
"Obviously it's for the gaffer to get the potential out of us over the next few games and next season."
Source: BBC Sport
Source: BBC Sport