jeans, specifically jeans so tight that your dong is rocking out. hence the term, smuggling bananas. See Journey circa 1978.
"man i got these new banana smugglers but the waist is a little tight. i'm starting to black out."
1.) When you have an obvious boner in pants too small for you and it shows.
2.) When you wear pajamas from four years ago and someone notices your junk.
3.) When in a Co-Ed gym class, a girl bends over and you have to sit down to hide your massive erection.
1.) Banana Smuggler - "Wow. look at these pajama pants, they still fit!"
Step-Father - "Are you smuggling a banana?"
2.) Self explanatory
3.) Girl - " WoW! I dropped my phone" ( Bends Over )
Boy - Oh damn.... ( Sits down to hide boner )