When Miss Stephanie and Atticus notice that his pants are missing, Dill quickly steps in and says, " We were playin' strip poker up yonder by the fish pond" (54). To their relief, "[t]he neighbors seemed satisfied" (55) with that answer; at least all were satisfied except Miss Rachel, Dill's aunt, who was about to go at him when Atticus stepped in suspicious that the kids had never played that before. Quickly thinking, Jem stepped in and said they ahd been playing with matches, not cards, realizing as Scout observes, that "[m]atches were dangerous, but cards were fatal" (55) in the disapproving eyes of adults.
Jem went back later to get his pants, yet upon his return seemed strange and said nothing to Scout about what he had encountered when he went back. It was not until a week later when school started that Jem finally spoke up and told Scout " When I went back for my breeches -- they were all in a tangle when I was gettin' out of 'em, I couldn't get 'em loose. When I went back -- ... they were folded across the fence... like they were expectin' me" (58). This leads the reader to believe that it was Boo Radley who had placed the pants on the fence for him, having been watching the kids' antics yet again, just like earlier when he was leaving gifts for them in the tree on the Radley property.
dill said that he won jem's pants by playing strip poker. Jem goes back to the Radley's place to get his pants at night.