If your holster is made to keep your, um, fat (there: I said it) from wiping the safety lever to "off," then you've got no worries, mate.
A proper holster for a gun carried in single-action "Condition One" (loaded, cocked, safety on) has a place in its leather (or Kydex) into which the safety lever fits when "on."
If your holster doesn't have that, I suggest getting another holster: One that does.
If your holster is leather, and it has a "sweat guard" that covers the safety lever, but the "sweat guard" is not molded to immobilize the "on" safety, you can dampen the leather in that one location and mold it around the "on" safety. Then let the leather dry out completely in a cool, dry location (using no heat at all), and you're all set.
If the holster is plastic, you might try to re-mold the safety area using a heat gun or a hair dryer. I don't hold out much hope, because it's very easy to melt the plastic, rather than remold it.
Pressure on the gun's hammer won't cause a negligent discharge, as long as the safety lever hasn't moved to "off."
BTW: There are no dumb questions. Well...the same question repeated for the third time is dumb, and not wanting to ask because you think that asking the question might make you look dumb is dumb, but no question is dumb.
If you want to learn, you need to ask. Period.