US black comedy movie

I'm trying to trace a US black comedy from the 1990s where a teenaged boy is obsessed with a fellow (male) school mate. He tries to ingratiate himself with the older boy by giving him free vodka for a party, but later hits him with his car and believes he's killed him. He takes the 'body' home and has sex with it and then tries to remove a ring from the body's finger by cutting it off, at which stage the 'body' wakes up. Sounds awful, but it's actually very funny.