I was disappointed at Gerald's lack of presence in the Phoebe fart episode. He could've made the episode a lot better and sweeter. Here's how I would've done it.

When Phoebe farts in the microphone, Gerald, unlike the other kids who laugh at her, gets a weird feeling in his pants. When he sees Phoebe humiliated with no one else persuading her, he mentions to her how he was turned on by it, which gets Phoebe to cheer up and become happy. The episode ends with Gerald and Phoebe laying on the bed alone in the latter's room together, laying on the bed together with Gerald playing with Phoebe's plump bare butt as she repeatedly farts for him, bonding together as a result.