I have actually done that in real life. I was 16, just left school, but still didn't have a job. My mate had been thrown out and he'd got himself his own flat on Darnhill. I went up to see him and was introduced to weed for the first time. After spending an hour smoking it and 2 hours throwing it all back up, I went to catch the bus home.
It was my first ever time smoking weed and I was convinced that everyone would know I was stoned. So I was determined to act straight. I sauntered over to the bus stop, which had quite a few people in it and nonchalantly leaned against a non existent window. I dropped like a sack of shit but bounced back up as though I'd hit a rubber floor, so determined to appear normal.
The couple of old biddies in at the bus stop were so concerned, but the girl my age couldn't stop fucking laughing. I was that embarrassed I ran off down the road and ended up walking home. I even ducked into a doorway when I saw the bus coming past so they wouldn't see me.