I was on co commentary that day. The general consensus seemed to be that he’d said something along the lines of “do you want me to show you my (something) c**k as well” when he was lazily showing his studs and undershorts to the liner.
Liner waited for him to go on the field before calling the ref over. Which he shouldn’t have done. He should have immediately informed the referee and stopped the substitution with Robinson being sent off from the bench. Which would have allowed us to bring on another player.
I guess the liner just didn’t want to say anything while Robinson was next to him. Coward.