The lower part of your thumb that connects it to your hand. The thiccle is usually thick and squidgy, if you put the thumb to the centre of your hand it becomes easily visible.
Often preceded by the adjective "Dummy," this slang term may refer to especially dense underbrush such as when describing an outdoor environment when participating in Role Playing Games (i.e. Dungeons and Dragons, Pathfinder, etc.) This term may also be used to refer to a small hairy person with a large backside, as they may resemble the Ewok "Wicket" while demonstrating the quality of being "Dummy Thicc."
“Oh shit! Looks like those Bollywogs are clapping through the dummy thicckets towards your party. Roll for thicc save”
12 step recovery jargon referring to someone new who talks about how great life is, now that they'resober. Usually meaning that the person is out of touch with reality.
The new guy seems pretty happy for a dude who has no job, no money and no family. He must be on a pink cloud.