Reviving this thread after finding it using the search function. Will probably set myself up for all sorts of ridicule but here goes.
Basically an exact rerun of the OP. Happened to me last week.
Player handballs on the line in a DOGSO situation. Arms up and away from body. Certain goal stopped.
I blow the penalty and then explain in a nice calm voice I'm going to red card him. Objections from him and the captain but I say I have no choice he has to go. Pull out the red and show it to him. Turns on his heel and as he's walking away (probably 1 to 2m from me) says loud enough for most of the players to hear 'you're a f#ckwit'.
So I give a quick toot of the whistle and show him the red again.
At half time coach comes on a says did you give him a second red? I said yes he called me a f#ckwit. Coach says, oh Ok then.
Now I know you're not meant to show 2 reds but my logic was all the players have heard that, I need them to know I've heard it, it's not on and I'm dealing with it.
At the end of the match I just wrote in the match report Red (R4) for DOGSO handball, Red (R6) OFFINABUS towards match official.
Probably wrong to actually show 2 reds but that was my thinking.