kick off wedding

Two guys are talking about their boss's upcoming wedding, and one says,
"It's ridiculous! Sure, he's rich, but he's also 93 years old, and she's just 26! What kind of wedding is that?"
The other says, "Well, we have a name for that kind of wedding in my family."
"Oh, yeah? What do you call it?"
"We call it a football wedding."
The first guy asks, "What's a football wedding?"
The other guy laughs and says, "She's just waiting for him to kick off!"