I got a letter just the other day She sent a picture, but she didn't sign her name She wore high heels and a little black lace I knew her body, but I couldn't see her face She didn't leave a number, not an address or a clue But something in that photograph reminded me of you Baby, let's put the X in sex Love's like a muscle and you make me wanna flex Baby, let's put the X in sex Keep it undercover, baby let me be your private eye I got a call in the middle of the night Heavy breathin' never sounded quite so nice She said "Ooh yeah, I wish that I was there" I asked who was calling, but she wasn't playing fair Sometimes you gotta suffer for the pleasure that you seek You're beggin' for an eyeful but you only get a peek Baby, let's put the X in sex Love's like a muscle and you make me wanna flex Baby, let's put the X in sex Keep it undercover, baby let me be your private eye Oh yeah (yeah) I heard somebody knockin' so I opened up the door She wore a hat, shades and a trench coat, wasn't wearin' that much more She said she knew my secrets but I didn't have a clue Then I saw those black lace panties and I knew that it was you Baby, let's put the X in sex Love's like a muscle and you make me wanna flex Baby, let's put the X in sex Keep it undercover, baby let me be your private eye Let's put the X in sex Love's like a muscle and you make me wanna flex Baby, let's put the X in sex Keep it undercover, baby let me be your private eye Let's put the X in sex Love's like a muscle and you make me wanna flex Baby, let's put the X in sex Keep it undercover, baby let me be your private eye Let's put the X in sex