Massage her shoulders

(Dudley's POV)You need to stay cautious hence you walk towards her and starts massaging.

Petunia who was in grief didn't respond well but regained herself. When she looks onto you, she starts wailing," Oh Diddykins. Who will look after me now? All I have is that wretched boy who I think might have done this."

You respond as commanded, "Don't worry mom. I have locked him up in the attic ever since he came because I was afraid of him. I'm sure it wasn't him but it's best to be cautious."

Petunia wipes off her tears," Vernon broke off my promise. He said that today he wou--".

Petunia stopped quickly and turned red. You,as Harry, used occlumems through Dudley to read it quickly only to find out that after 7 years it was the first time they would have sex. But due to the issues she couldn't.

You then command Dudley to act innocent and respond," he would what mom? I feel I can help you. After all, I'm your Diddykins."

Petunia started breaking down. Her knees were weak and she fell on the ground weeping. This provides another opportunity. Expose her vulnerability and play brutal or play on the good son?