When someone is in an assumed committed relationship where you don't want to not let them know you are still "looking around" or clubbing and you sneak out during the week to see someone else. This means you are going out on a Thursday night with another person for sexual interests or going clubbing to find one. If your current gf/bf or serious dating person asks to hangout, you play it off like you have no time for them because it's a Thursday during the work week and that you are staying home. You look completely innocent because it's a Thursday but you have to sneak it in on a Thursday to maintain the normal schedule with her/him during the weekend.
This is not where you say a "guys/girl's night out"
Known statistic: In Los Angeles people go clubbing more on Thursday's than any other day!
Example 1: Honey I can't hangout tonight I have work early tomorrow. When I was really thinking, Girl I need to do a Thursday night sneak.
Example 2: Hey Troy, how was your Thursday night sneak yesterday? It was sweet, my girl will never know. I get to see her tonight as usual, (Friday night).
Example 3: Shit, This bar has tons of hotties all GF material. There must be tons of Thursday night sneaks here right now.