Grammatically, both sentences are okay. But in terms of word choice I would say that you can't wedge something "between your pants" -- although "pants" looks plural, it's really a single object. You could say "wedged into his pants" or, even better "wedged into his belt."
I thought this might be quote from a Robert B. Parker novel, but his books are narrated in the first person, from Spenser's point of view. If this is something you are writing about a Parker novel, please note that it's Spenser with an "s". And if Parker actually used the phrase "a gun wedged between his pants," I'm surprised I didn't notice it when reading the book. (I think I've read them all.)