Handheld Trigger For Marking Locations

[garfishswims]

Hi!

First time poster here.  Has anyone ever come across a "handheld trigger" of sorts for marking a crap ton of points? This is probably silly, but I want to mark litter locations in a park I frequent, but I don't want to pull out a handheld gps receiver, or my iphone, literally hundreds of times during a typical walk.  I guess I'm envisioning an accessory for a handheld gps receiver or my iPhone.  I'm curious to see if I can map some useful information while I pick up litter... it might lead to a new location to place a trashcan or signage.  Who knows?  I've seen photographers utilize remote triggers but I'm not entirely sure how I could use that to capture a location.

Any thoughts or suggestions are appreciated!