When you only have one more day until Friday, but you just can't wait so you start on Thursday.Everyone enjoys getting drunk on beer and having fun.
"Noah and Joey will be out every Thursdrunk until the end of time,Join us"
When you just can't wait until Friday to start your weekend partying, and end up getting "Thursdrunk". Normally involves calling in sick to work or school Friday morning, or at least going in with a 'slight' hangover
Robert has had such a rough week that he's not going to be able to wait until the weekend to party, so I'm sure he'll be Thursdrunk tonight, and be calling in sick to work on Friday morning.