I should have known the relationship was doomed the moment he brought up his all-consuming hobby: race car driving.

I spent an entire summer in the sticks of Ohio and Pennsylvania, feeling like an idiot as my then-boyfriend Sam, his dad, and a friend worked on the car, which was black and blue and with a giant wing on top. It looked like an alien bug on wheels. The first time I came to a race, his mom told me to dress casually, but my outfit (jeans, a striped t-shirt, red flats, and big sunglasses) might as well have been a ball gown compared to the giant silk-screened shirts everyone else was sporting. Sitting in a lawn chair in the driver pit, I folded the cover of the New York Times magazine to hide the abortion cover story and offered everyone soy nuts. From the stands, I watched cars flame out, crash into each other, and kick up dirt. I prayed for one of the cars to mow me over and texted all my friends, “One of these things is not like the other….”

The morning after a recent tryst, I was mortified to find two giant purple hickies on my neck. Even more painful: I limped through the rest of the weekend because we had gotten a little (ahem) enthusiastic in the sack. Determined to avoid more bedroom battle-scars, I turned to science to find out how to get off without getting injured. My tricks, after the jump…

I only think about my underwear in the millisecond when I yank them out of my dresser drawer in the morning. (Thong or no? Is this going to ride up at the gym?) My bra never matches my out-of-season holiday panties or my cotton boy shorts with a French poodle printed on the butt saying, “Ooh la la!” But whenever I’m in a serious relationship, I give painstaking consideration to my unmentionables. I’ve gotten on a plane wearing an elaborate black-and-pink lace getup under a T-shirt and jeans to meet my boyfriend, and shown up at his doorstep wearing nothing underneath a dress.