Kansas State University has come down hard on the director of the marching band ... suspending the guy for using a formation that looked like the rival Kansas Jayhawk was performing oral sex.

After video of the formation from Saturday's KSU vs. South Dakota football game went viral -- the director claimed the formation was supposed to be a battle sequence featuring the Starship Enterprise attacking the KU Jayhawk -- KSU's biggest rival.

Sure.

Still, as our friends from BSO pointed out ... the school has decided to punish the band -- suspending the director for one game and fining itself $5,000 which will be paid to the Big 12.

Sucks for them.