Goal: get rid of all your cards. The last player still holding cards loses the round.
All 52 cards are dealt out. Aces are high.
Whoever has the A♠ starts by playing it. In this first round everybody plays a ♠ if they can. All these cards go to the pile, even if someone had no ♠.
After that, the leader plays any card. Everyone else must play the same suit if they can.
If everyone follows suit, the cards go to the pile. The highest card of that suit starts next.
No card of that suit? Play any other card — that's a Thulla! The round stops at once, and the player with the highest card of the suit that was led picks up every card on the table and starts next.
Play your last card and you got away — you're safe!
But you can't get away while you have the lead: if your last card wins a round where everyone followed suit, you take a random card from the pile and must play it.
Tips
Low cards are safer. When someone gives a Thulla, the highest card picks up.
Watch who gives a Thulla — they have run out of that suit.
Being last to play in a round? Nobody can Thulla after you, so throw your highest card of the suit.
Rules follow the version described on pagat.com (Getaway / Bhabhi). Option: “Last card always gets away”.