Simple:
* The garbage stunk so bad I had to hold my breath.
* The old shoes stunk of sweat and mildew.
* The meat stunk after being left out in the sun all day.
Figurative:
* His excuse stunk of lies and desperation.
* The whole plan stunk from the start.
* The atmosphere in the room stunk of tension.
Past Tense:
* The milk stunk so badly, we had to throw it away.
* I stunk after playing soccer in the hot weather.
* The old book stunk of mothballs.
Note: "Stunk" is the past tense of the verb "to stink". It's important to use the correct tense depending on the context.