This is a pet peeve within the Jiu Jitsu culture. When someone has a solid offensive position (near submission) the person who is in trouble may start giving advice to the person.
There is a time and a place for coaching and rolling is generally not the place unless its is obvious you are at a level where you can help this person and the only way they could possibly get the position is if you gave it to them.
Still it is not always within the Jiu Jitsu code to help them at that time.
Most help should come after the roll or after class. Out of respect.
What do you think about coaching people when you are about to get tapped?