“Guys” can refer to a lot of things, usu. weed, beer, and cigarettes.
Ex: “I’m down to my last two guys, I should stop at the OP and pick some up.” or “Pass me a couple guys.”
“Put some guys on it” specifically refers to pot, however. Usually said when trying to come up with a plan or figure out rides or solve any number of simple tasks that become increasingly difficult to manage due to the inverse relationship between sobriety and basic problem-solving skills and everyone would just rather pack another bowl than decide right away.
1: “Where should we go to eat?” 2: “I dunno, put some guys on it. It’s fine."
1: “So what do you want from Sonic?” 2: “I dunno, man, we got guys on it, it’s fine.”
1: “What movie should we watch?” 2: “Fuck, man, put some guys on it. Gives me time to think. It’ll be fine. We got guys.”