It depends on you and your partner's comfort level. Some couples are shy or reserved, and would prefer not to show affection in public at all. Other couples are not shy and can't keep their hands and lips off of each other, Is there a happy median? Honestly, there is no right or wrong way to show affection to your partner, but generally keeping it "PG" in public is a good idea. Affection comes from the heart and people show it in different ways, but whatever you do, make sure you don't make your partner feel uncomfortable. The last thing you would want to do is embarrass them. That would defeat the purpose.
Here's a Tip: Keep it classy. Save the extra mushy, extra sappy stuff for a more intimate setting. I'm not saying anything's wrong with a playful pop on the butt and the chase that may ensue afterwards. I'm saying if it's turning into foreplay, get a room.
I've always believed that there's a time and place for everything. Corporate parties, religious celebrations and children's functions are probably places you want to tone down the PDA a little bit. Goal is not to get arrested, LOL. Remember, PDA is natural, so just be mindful of your surroundings and of your partner's feelings.
~Your Favorite Wedding Officiant~