I also start with squats but was thinking of changing this as I saw in walking beasts journal here that he does leg extensions as a warm up before squats and that makes sense to me.
I do leg extentions first to warm-up my knees, then squats, then maybe some type of leg pressing machine. Whatever feels best though. My knees dont feel right unless I warm them up on the extentions first it seems. Also depends on your goals. Im assuming its just for bodybuilding purposes, so strength is probabally not the biggest concern.
You could definitely hit the extensions as a pre-exhaust before squats (but keep it light). I personally like to warm up with light squats and then jump into it and then as chink said, do extensions after, as an auxiliary lift.
Well, I do leg extensions first. I do go heavy and make sure everything is warmed up and pumped! I then do squats as heavy as possible. I then finally do leg presses all fucking out!!! I fucking yell, scream whatever it takes to leg press as much as possible. Just thought that maybe I should do leg ext last.