You're like 95% sure it's just gas. Pretty sure it's just a fart.
...but you decide to sit down on the toilet JUST in case. 95% of insurance shits usually end in something productive, and can save you from the ever-embarrassing shart
Rick: Okay okay okay ready I got one, get the lighter...
Rick (cont'd): HOLY DICKSWEAT THAT WAS AMAZING!!
Roll: Okay lemme tr-...wait...wait...nope, I've gotta take an insurance shit.
When you take a shit either A: so you don't have to later on while there is no time or B: are not sure if you have to fart or have to shit so you go do it on the toilet.
A: "Dude, I'm not sure my bowels will make it the entire road trip without me taking an insurance shit before we leave"
B: "Dude, I'm not sure if I have to fart or crap so I'd better go take an insurance shit just in case"