How does Dill claim Jem lost his pants ?
In chapter six of To Kill a Mockingbird, the gunshot from the Radley place brings all the neighbors out into the street, where the children also show up, Jem without pants.
As the dust settles and smoke clears, Miss Stephanie is the first to notice Jem's lack of clothing. Dill comes to his rescue when he explains that they were playing "strip poker" with "matches" in Miss Rachel's yard (54).
This story of Dill's is a plausible yet still punishable offense for the kids, but as an alternate to the truth a relief for Jem.