"We're not trying to have sex on the dance floor. We're just trying to have a good time," senior Josh Partridge said.
Various Detroit-area schools have tried to deal with freaking, in which dancers mimic a sex act as they rub against each other, the Detroit News said Thursday.
Brighton High School students were asked to sign the contracts by the school administration.
Some parents say they believe the reason for the crackdown at Brighton High is that it is the will of the new superintendent, Greg Gray, 37, who started the job in July. Gray did not comment on the matter, the News said.
The school administration and student leaders said they are working on new rules they hope will be acceptable to both sides before the May prom.
Pinckney Community High School asked students to sign a similar contract and drew half its usual attendance at a winter dance. Plymouth-Canton Community Schools also require a contract, the News reported.
Brighton had only 67 students sign up for its Winterfest dance in February, for which the ordinary attendance is 1,350, the News reported.