If you have to deal with rapidly moving objects or other material for which tracking does not produce satisfactory results the keyframing technique is what you want.
In Traxim Unplugged the color of frame number in Render Rosition menu is a keyframe indicator. When you created a matte  you probably noticed that keyframe indicator was set ON automatically.

Every time you click Create Matte you make the current frame a keyframe.  To delete a keyframe simply click Erase All.

1. Start Traxim. Notice that initially Keyframe if set OFF.
2. Draw an outline of the flower at Frame 1. Note: Unlike tracking keyframing can be done for a single object only.
3. Create a matte. Notice that Keyframe is set ON.

  4. Play the clip forward to to Frame 5 and repeat steps 2 and 3.

5. Play the clip back to Frame 1.

6. Tween the clip forward. Watch frames 2, 3 and 4 as they are being tweened.

7. At the Frame 5 the process is interrupted. If you click TweeF again you receive the error message:

This message means that no more keyframes have been created in that direction. In order to continue tweening create keyframe(s)  ahead of Frame 6 ( for example at frames 9, 14, 19 and 24). Then return to Frame 5,  set Keyframe Enable ON and click Play Forward.

8. Traxim can do keyframing both forward and backward. The result depends on the direction though: the result of keyframing from Frame 1 to Frame 5 is slightly different from the one obtained with keyframing from Frame 5 to Frame 1.