I ususally go with my 2nd opinon on the game, i.e, how I think the game will go. Over under, spread, etc.
I will use the Tarheels as my example, since that is my team that would be a situation I bet against them the most.
1st off, its hard to do, but if you really know your team, you should know when their "best chance" to lose is.
The next, will be your reason fo doing it.
SOmetimes its a "look ahead, let down" or just a team they don't play well against. Others, is match up.
Last, does come down to % of what you are betting.
If this is just a normal game, I bet it the same way as if I was on the other side. (my normal bet is 2-3 Units, 200-300 in college football/basketball). Now, others, I have made a HUGE play against one of my teams. I made only 3 10 Unit wagers in ALL of college football last yr, the last being against RU and taking Neers to win.
it really just comes down to why you like the play. If you really want to make money off your team losing, you should play it like they are really going to lose, like you said.
To me its really like selling your soul to the devil, or Judas, if you are going to be rooting for your rival and all that it takes to do this is 30 pieces of silver?
I don't think you are a real fan than
Just my opinion