We have come to expect that you will provide us with the "infectious jam of the summer." (See: "California Gurls," "Last Friday Night (T.GI.F.)"). With this year's "Birthday," you have exceeded yourself - on multiple levels.
Catchiness? 10 out of 10.
Saturation with double entrendres?
There's, like, two phrases in the entire song that won't make me cringe when my nine year-old sings them from the backseat.
I especially like the part about getting your significant other* into his birthday suit so you can bring out the "big balloons."
You're talking about something like this, right?
Yeah, I didn't think so.
* At least your significant other is no longer that Massengill-hygiene-product-in-human-form, John Mayer. He was harder to explain than your lyrics.