You can do this when you want to pause El Jefe’s mission’s. This helped me personally to be able to afk a bit without the worries of El Jefe’s goons coming to rob my weed store or loosing rep to him.

When you get the El Jefe mission you need to do and deliver something to him, like Blueberry Crossjoint’s, Bongs... These have a time limit and if not delivered in time you will lose rep to him. However there is only one of these missions with you can complete and stop the timer, this mission is the "Take Care Of 6 Bums" this makes you need to kill bums found from the street. When completing this mission El Jefe will send you a message saying "Good job, holmes! Way to smoke those bums. Now come pickup your bag" Unlike every other mission this stops the timer when all bums are taken care of and you can go pickup you’re pay when you want.

To do this you just need to wait until you get the "take care of - bums" mission take care of the amount of bums needed and just don’t go and pickup you’r pay from El Jefe.