You know it isn't "Legos". You've had FUCKING YEARS to adjust to the actual, correct way to say the term. It's Lego. Lego bricks, Lego sets, Lego kits, Lego mini-figures, Lego City.
There are no such things as "Legos". They don't exist. "Lego" refers to the COMPANY THAT MAKES THE TOY, and thus the shortening *Lego* is acceptable. Saying "I'm playing with my Lego" works because it's referring to the sets themselves: The individuals aspects that make of the toy from the bricks to the mini-figures to the electronics to the other little parts. It isn't claiming that the fucking square bricks are each a Lego. THE ENTIRE THING IS. If you were to say "I'm playing with my Legos" that implies that you're playing with at least two different types of Lego set at once, i.e. Lego City and Bionicle.
Still saying LEGOS after all these years makes you look like an assclown. Here in Europe, the continent responsible for this toy (no, it wasn't made by America, no matter how much your capitalistic toy industry wants you to think), you'd be laughed out of the room if you said that.