What Is Trump?

In my gaming group we love to play a card game we either call 'Prediction' or 'Up and Down'. I'm not really sure what the right name of the game is. My sister learned it a long time ago on a trip through Africa from some of her fellow travellers. Basically, each round you play with less and less cards, while the trump suit also changes each round. Goal is to predict how many tricks you will make each round. Correct prediction will give you five points, while each trick you make will give you another point.
(I did some digging and found that the games 'Oh, Hell' or 'Up And Down The River' seem fairly similar to our game - though there are some variations still)
Prediction is our fall back game anytime we are not able to play our usual roleplaying game because one of our group is not available.
As the suit which is trump changes every round, a very common question is: "What is trump?"
For which I now have the perfect solution:

Suit coasters!!

I used felt and applicated the suit color using my sewing machine. On the backside I sewed some soft leather.