11:17 AM PT -- Cops in Washington, D.C. are investigating the incident as a lewd act.

In the police report, obtained by TMZ, cops say the homeowner called to report the incident around 5:30 PM last Friday, telling cops the guy stuck a cucumber in the grille of her car and used the vegetable to perform sexual acts.

Cops say the suspect also performed lewd and obscene acts on the cucumber at the back of the car ... before leaving the scene.

Groceries are not as affordable as they used to be ... but, they're still remarkably cheaper than sex toys -- and, one man was caught on video enjoying the less-expensive option.

A man near Washington, D.C. appeared to abuse his lunch last week ... video captures him ducking through a broken fence with a lunch box in hand, placing it on a small flight of stairs.

Check out the clip ... the man walks over to the front of a car -- taking a cucumber with him, and appears to shimmy the veggie into the car's grille.

It's hard to see exactly what this individual does ... but, while looking around to make sure he's alone, this person turns around, appears to drop his pants ... and does a shimmy of his own, rhythmically bouncing on the makeshift sex toy. He then enjoys a post-session cigarette.

He eventually grabs his cucumber, puts it back in his lunch box and heads on his way -- but not before a bit of round 2, it seems. No word on the fate of the cucumber, but we certainly hope it ended up in the trash ... and not in someone's salad.

Catherine Baker, the woman who owns the home where all this went down, spoke to DC News Now ... saying she wants people in the area to be aware and vigilant of this kind of behavior on their streets.

This individual walked away from the scene cool as a cucumber ... but, this security footage may land him in a bit of a pickle!