The bet will always be a fav. So let's say you play to win 100.00 and the bet is -1.50. If you win game 1 you are done. Cash you $100.00 Ticket.
If you lose, your 2nd bet will be 150.00 + the 100 you want to win at let's say even money. If you win, cash your $250.00 ticket.
If you lose your 2nd bet, your 3rd bet will be 150.00 (1st bet) + 250 (your 2nd bet) + 100.00 the original goal.
As you can see your 3rd bet can be pretty cute. Like if 3rd game is Kershaw @ -2.00.
Hope this helps.
I still remember Houston taking a 4 game sweep on LA Angels 2-3 years ago. Angels big favs every game. Still have betting PTSD over that one. I assume Hook em remembers that series also.