A last minute change of plans or possibly risky judgement call between a group of best friends pertaining to their plans for the evening. Based on the saying 'carpe diem', or 'Seizing the Day'. Usual partners in crime include rum, tequila or both and a walk of shame from a significant others house the following morning.
"Instead of sitting inside on a Wednesday evening and doing nothing, lets go to the bar down the street, get rip roaring drunk amongst friends and strangers, and then let hot guys buy us drinks and take us home."
"Now that's seizing it like no tomorrow! Be ready in 10!"