. . . "button" ?? Are you talking top of the smallest section.
I own two different length ASP's. Both lock up so tight that I have to bang 'em down on concrete or hit them with a hammer to get them started collapsing.
The ASP brand is a super heavy duty weapon.
Best of luck with your sale sir. --- SAWMAN
Yes sir, it's the tip of the striking portion of the baton. I close mine the same way, a straight sharp press onto the ground..tends to score them a bit but they lock up so tight it's the only consistent way I've found