To drink so hard on a Friday, that you don't recover till about noon... on the following Monday.
To be so hungover that you miss work the next day.
To raid your $50 a bottle mini-bar.
To jump in the pool with your phone in your pocket.
To have a great time.
"This project is such a mess, I feel like pulling a whelan and not even showing up tomorrow."
"I thought I had lost my phone, but it turns out I just pulled a whelan with it last night."
"I pulled a whelan with my mini-bar and didn't even make it out of bed for days."
"Work is killing me, tonight I need to go out to whelan hour."
"I drank so much, I thought I had whelan poisoning."
"Why didn't Mike show up for work? He's pulling a whelan."
"I can't wait for this weekend, we're going to take a taxi so we can all get whelan at the bar."