I think you mean bogging the engine.
Generally, you don't want to do this as it is stressful to your engine. An example of bogging or lugging the engine would to be trying to climb a steep hill when you're in 5th gear, going at about 70km/h. Your engine will not have enough power to make it up the hill without causing detonation and pinging.
This is bad.
If you're approaching a stop sign in 2nd gear, just coast in 2nd gear until you're almost at a complete stop. Press the clutch in and voila - you're done. If you don't press the clutch and your car sounds like it's about to stall, you're bogging the engine - that's bad.