Sure, you may be game to go at it 24/7, but all guys have heard those two most dreaded words: “Not now.” “Everyone is tuned to enjoy sex the most at different times of the day,” says sex therapist Sari Cooper. “Our natural biorhythm determines when we’re in the mood, and there are benefits we can reap whether the sun is shining or the moon is out.” So here are some compelling arguments (backed by science!) to convince your girl that it should always be sex o’clock.

Rise and Shine

Getting out of bed is hard, but so are you. The reason most men tend to wake up physically ready to go is because blood circulation to the penis increases overnight. Instead of tucking it in your waistband and shuffling to the shower, be up-front and tell your girl how much you want her. “I know it’s biology, but there’s nothing that makes me hornier than feeling my boyfriend when he’s completely hard,” says Annie,* 27. “I love crawling on top of him and going at it like crazy. ”It’s also a fact that men’s testosterone levels peak after a night of rest, which means you have more energy and can last longer. Plus, you’re already in the bedroom, so you might as well make the most of it. “Don’t worry if you stress about time,” Cooper says. “The rush of getting out the door is a huge turn-on for many couples.”

Afternoon Delight

“People who prefer midday sex are those who can take the time to get themselves into a very relaxed state,” Cooper says. “It’s like taking a spa day”—literally. Getting your girl to orgasm releases chemicals that boost levels of estrogen, the hormone that keeps her hair shiny and her skin wrinkle-free. So if your lady loves being pampered, go on and indulge her in bed. “There’s nothing more calming than spending an entire Sunday playing around in bed, in a bath, wherever,” says Lea, 29. “Why flip channels when you can flip between napping and making each other come?” Midday sex is also perfect for adventurous types. Since traditionally we think of sex happening in bed at night, daring to sneak in some lunch-break nookie can be a thrill. Your heart rate and adrenaline will be rushing, making the release extra intense.

Evening Seduction

Is your girl always cranky after work? Instead of hiding in the next room, why not suggest “lying down together” for a bit? Since orgasms release the feel-good chemical oxytocin, some sweet lovin’ may be all she needs to brighten her mood and change a night of nagging to a night of, well, whatever you’re into. “After a bad day, I usually change into sweats and watch House Hunters,” admits Janet, 28. “But one night my fiancé bent down and started kissing me as I lay on the couch. At first it was annoying, but once he got down there I just gave in, leaving me feeling completely blissed out.”

The After-Party

Coming home from hours of drinking and flirting is usually an invitation for a wild hookup. “Most women find nighttime sex exciting because that’s when any neuroses you have are muted,” Cooper says. If your gal is reluctant to get it on before work or when your roommate is watching Jeopardy! in the next room, save the sex for when the sun has truly set. Nina, 26, says her inhibitions are shed just as fast as her clothing once the clock strikes midnight. “Any hesitations about experimenting in bed are completely gone after dark,” she shares. “It’s when I’m the horniest and my inner freak comes out to play.” So go hard and go crazy, and then enjoy those z’s. Sex releases sleep-inducing endorphins that will help the two of you knock out after the action, giving you the energy for another romp in the morning. Sweet dreams!

*Some names have been changed.

Photos by Carlos Nunez | Licensed to Alpha Media Group 2014