This phrase expresses your passive acceptance of an event, initiative or activity that may or may not require your involvement. A more creative, flavourful and eyebrow-raising way to say "it doesn't bother me", "meh" or "I don't care".
"If you want to spend the night in jail, fine, it's no jizz on my chin."
"I'm driving by there anyway, so it's no jizz on my chin to swing by and pick you up."
"Hey, it's no jizz on my chin if you want to visit that priest, but don't say I didn't warn you."
An emoti-acronym used for situations where "LOL", "LMAO", and/or "ROFLMAO" just doesn't quite express the fit of laughter you are experiencing. "GMB", or "Grabbing my balls" can be added to any of the aforementioned to adequately illustrate your uproarious reaction to what you have found to be overwhelmingly funny. Additional intensity could be expressed by adding an 'F' -- such as: "GMFB".
"LMAO GMB!! That's fuggin' classic!"
"What? She got caught jerking off the janitor?? LOL GMB!!!"