Summer Hansen couldn’t stop grinning and laughing as she pleaded not guilty at  Riverside Superior Court to a slew of underage sex crimes.

A California high school teacher accused of having sex with five students was all smiles when she appeared in court this week.

Summer Hansen, 31, couldn’t stop grinning and laughing as she pleaded not guilty to making out with the boys in her classroom, utility closet, parked vehicle and one of their homes.

The bubbly brunette also denied sending naked snaps of herself to the alleged victims.

And she claimed it was untrue that she’d offered sex as a “prize” to a boy who’d played well in a baseball game.

“Do teenagers lie? Sure they do. Do they say something and then really believe it and move forward? Yes,” her defense attorney, David Cohn, told Riverside Superior Court on Tuesday.

“These boys all know each other. If they didn’t know each other and had no connection to each other, then you would start to wonder,” he added.

Hansen, a special education teacher at Centennial High School in Corona, was arrested in June and charged last month with 16 felony counts.

Posting bail, she was placed on administrative leave, reports KTLA5.

It later emerged that she did not directly teach any of the five alleged victims, all under age 18, but they did attend the school.

Cops were tipped off after rumors surfaced about an “inappropriate relationship” she was reportedly having with a former student.

If convicted, she faces up to 13 years in state prison.