Like this:
"I hope your birthday literally blows up your mind."
"I hope your birthday gets you everything you wanted in the world, to the point that you simply regret it all."
"I hope your birthday is filled with nonstop laughter, so that when you wake up with abs so sore that percocet won't even have an effect."
"I hope you are able to eat so much cake today that you set the world speed record to go from 0 to diabetes."
"I hope you are able to spend time with so many loved ones that when they come over, the density of bodies is so high that the lot of you reaches critical mass."