In the sport of American Football, after a runner has scored a touchdown (by carrying the ball past the goal line) and the play has ended, the runner sometimes celebrates. The celebration may be a little dance, or it may be throwing the ball very hard against the ground, so that it bounces high. That second one is called "spiking the ball" -- throwing it very hard against the ground as a victory celebration.
In recent years, in professional football, players got carried away with these celebrations, and rules were made forbidding them.
Ike is making a ridiculous suggestion: that Maggie will "spike" the bouquet of flowers to celebrate her "victory" of getting married.