I've carried them just in the pocket.
The rounds have never "come loose," but I don't like the way the strip floats around in my pocket, and I never know where in my pocket it will end up, or what position.
I suppose its better than an empty pocket.
Simplyrugged.com makes a really solid snap-pouch that will secure your clipped Speed-Strip ammo on your belt.
Some folks use the cordura/velcro pouches that are commonly used on duty belts to hold rubber gloves for frisking funky felons.
Remember too, the premise of still carrying a revolver in this day and age is the notion that 5 shots should be plenty to deal with whatever comes up.
Which I have found to be true in my half-century of travels.
I still occasionally walk around armed to the teeth - just because I can - not because its likely to matter.