How would you react to an E2 who "smart mouths" you in formation?

When I was active duty it wouldn't happen but this is what is wrong with America. Children aren't disciplined at home and grow up with no respect for authority and do not understand the consequences of doing the wrong thing. In my day someone would beat that ass or IPT until they wished they were dead.

Have the PFC kneel in a corner, and have the sgt seek counseling or an office job.

write up for insubordination and refusal to obey a lawful order then let the commanding officer take it from there.

I would calmly give the task to someone else. And deal with the private privately after formation. I will never have another problem with him again.

This as it is written, will not work, you start out with an E-2 and then go to they, so are you talking about one person? Or the entire group?

Simple, HALF RIGHT, FACE! FRONT LEAN AND REST POSITION, MOVE!

When I was in the E5 would take off his shirt and walk behind the building!

Seriously, this should not even be asked.

PFC toast for breakfast

I was in that position as an E-3 over an E-1. As an MP we are to make sure all facilities are locked and secured. I noticed on patrol a national guard armory door was opened. I called for back up and told the e-1 to take up a position to watch for anyone who may come out while I took up a position to the other side. The E-1 instead rushed the door before back up arrived. Of course I had to have his back and come to find out the armory was empty. We arrived at the PMO and I dropped the e-1 off , told the desk Sgt what happened and told him I didn't want him riding with me and that I prefer to ride alone. Desk Sgt told me okay for this shift. The next day the company commander called me into the office and told me that the e-1 said that I was the one reckless and that he was afraid to ride with me. I think I squared it away but I left any actions in the hands of the NCO's and Officers.
I also have been on the receiving end but I was accused of being disrespectful. It was a weekend and we were off duty, a specialist who had been partying in the barracks on the 3rd floor ordered me to pick up his mess in his common area. I respectively reminded him we were off duty and that I didn't cause his mess and I being on the 1st floor had my own mess. To be honest I thought he was drunk still. I turned around and went back downstairs. Later that day he at the urging of a squad leader gave me a counseling notice which I refused to sign. It said that I had disrespected a "higher ranking person" and that I mouthed off and said I didn't want to be in the Army. I was furious and this specialist from that point on was considered a jack-ass by most of the company.