Y no te doy otra nomas - I don't hit you again just because... ](its incomplete on purpose)
"Chusma" means like people not worthy of you hanging with them, like poor or just not good enough, its a despective term.
Sin querer means doing something without wanting to do it, probably as a mistake. Queriendo means the opposite, it means wanting. When el chavo says s"in quere queriendo", it means he wanted to do something, but he didn't wanted the outcome of that action to happen the way it did.
"se me chispotio" - I made a mess