Dirty Bertie: Pants! - Alan MacDonald

Goodreads 4.1

Dirty Bertie's third book finds him facing the shame of losing a dare with Know-All Nick and having to wear his pants to school, playing the part of the dog in the local amateur dramatic society's production of Oliver! and taking Whiffer to Royston Rich's birthday party, where Whiffer leaves a very unwelcome present...