Someone has a lot of time on their hands
I think what he's trying to say is: If one guy fouls the other guy, then you have a foul.
Easier said than done sometimes. Lots of jockeying for position in the low post. Look for someone being displaced. There's always the option of calling a double foul if they are both being naughty at the same time and you can't pick just one being more naughty than the other.