Court documents also indicate the social studies teacher sent nude pictures of herself to one of the students from her cell phone.
According to a search warrant, at some point during the sleep over, a digital picture was taken.
It allegedly shows 33-year-old Shannon Best kissing one of the students.
"I think that's really shocking," parent Tracey Ferguson said.
Ferguson's daughter is a senior at Sanderson.
"That's just not the norm," Ferguson said after taking a look at the search warrant. "Teenagers are out with their friends and going to mall, and they're not hanging out with teachers after school."
Ferguson was also surprised to read the passage in the warrant stating, "Ms. Best admitted to having a sexual relationship with [the student] for approximately the last 3-4 weeks. She admitted kissing and fondling [the student] and allowing [the student] to kiss and fondle her as well. Ms. Best admitted to test messaging nude photographic images of herself to [the student].
"It should never have happened," Ferguson said. "Cell phones, photographs, any kind of pornography. It's just not right."
Ferguson noted the search warrant indicated that the student allegedly involved in the sexual relationship with Best is 18 years old.
A school official and the law says even though the student is legally an adult, the alleged activity by a teacher is a crime.
"She knew better, absolutely without a doubt," Ferguson said. "They're still in school, 18 or not. They're still in school. And it's their responsibility to take care of your children."
The warrant says the girls slept overs at Best's apartment so she could take them to a track meet.
Best resigned from her job at the school earlier this week.