In State of Decay 2 (PC version), you need to hold your RMB in order to aim. This is cool for console players but not for PC players. In the majority of weapon-focused games, you have an accessibility option that says "TOGGLE AIM". If you turn that on, let's say in Battlefield 4 as an example, you just tap RMB one single time and it stays aimed, then if you tap RMB again like 5 minutes later it'll stop aiming. Basically the whole purpose of this option is to avoid holding RMB for 5 minutes.