Kissing can be a tricky, awkward business -- especially when you are a celebrity.

From Mariah Carey and Nick Cannon to George Clooney and Tilda Swinton and even to President Obama and his first lady, smooching on camera can make for one weird photograph.

A good kisser has an arsenal of techniques and can gauge the situation to decide which strategy to use, psychologist Maryanne Fisher wrote in Psychology Today.

But it doesn't seem as if anyone really took the time to gauge the situation in these photos.

Here are 15 of the most awkward celebrity kisses ever caught on film.