This was seen on a local area BBS nearly 40 years ago.

It was brought to mind when a fellow ham radio operator on a traffic net
I run on Fridays, mentioned he found "a rollerball mouse". That's an
antique, as most mice are USB controlled. But, as you'll see, I guess it
means that a mouse with balls is male, and without them, USB (ultra
sensitive b!+ch). <G>

***

(originally posted by Mark Clark)

From America Online...

The following is the text of an IBM internal bulletin. I'm not making
this up.

WARNING: Depending on where your mind resides, this could be VERY
SUGGESTIVE.

Abstract: Mouse Balls are now available as FRU (Field Replaceable Unit).

Mouse balls are now available as a FRU. If a mouse fails to operate,
or should perform erratically, it may be in need of ball replacement.
Because of the delicate nature of this procedure, replacement of mouse
balls should be attempted by trained personnel only.

Before ordering, determine type of mouse balls required by examining
the underside of each mouse. Domestic balls will be larger and harder
than foreign balls. Ball removal procedures differ, depending upon manufacturer of the mouse. Foreign balls can be replaced using the
pop-off method, and domestic balls replaced using the twist-off method.
Mouse balls are not usually static sensitive; however, excessive handling
can result in sudden discharge.

Upon completion of ball replacement, the mouse may be used immediately.

It is recommended that each servicer have a pair of balls for
maintaining optimum customer satisfaction, and that any customer missing
his balls should suspect local personnel of removing these necessary functional items.

Part number 33F8462 -- Domestic Mouse Balls
Part number 33F8461 -- Foreign Mouse Balls

... When I grow up, I want to be a retired lottery winner.
=== MultiMail/Win v0.52
--- SBBSecho 3.15-Win32
* Origin: The Thunderbolt BBS - Little Rock, Arkansas (1:2320/33)