There's no better way to say, "Hey Dad. I love you, but you smell like CRAP" than giving him a Bucket Of Cologne for Father's Day. We can't help you with the fishing trips he'll guilt you into after hurting his feelings by insinuating that he stinks, but we do have you covered in the B.O.C. department IF YOU KNOW WHAT WE MEAN :::WINK NUDGE:::
If you do ever decide to purchase a fragrance for your father, just be sure that you don't accidentally purchase the same fragrance for your college boyfriend a few years later. Take it from a girl who made that mistake. It'll just cause a lot of unnecessary awkwardness and weird feelings.