I pull the slide back (which happens to be FN's suggestion, but say that using the slide stop can be used as well). I do this because pulling back on the slide is more of a gross motor skill for me and it is universal on all my pistols. Some of the slide stops/slide releases on my pistols are in slightly different locations and a couple are a bit of a reach for my thumb.i see. that makes sense.
do you use the slide lock to release the slide or pull the slide back, seems like a lot of friction and wear to just pull the lock down.