This may feel very odd to you if you have never done kegels before. Keep in mind that it becomes easier and more natural with practice.
Remember that dropping your pelvic floor is the same action you use when you pee or poop, so relaxing these muscles should feel good. You can relax your pelvic floor muscles for as long as you are able. Try counting to 5 if this is your first time and work up to relaxing them for 10 or even 15 seconds.
Do not tilt your hips. Just lift them off the ground slightly.
If you experience discomfort and can only handle doing a few of these at first, that is fine! Start wherever you are comfortable and work up from there.
Keep in mind that you can do reverse kegels anywhere. No one will be able to tell that you are doing them, so you could do them while you are waiting for the bus, during a business lunch, or in the waiting room at the dentist.
Make sure to keep your gaze soft if you choose to focus on an object. This will help you to avoid creating tension in your face and possibly in other areas of your body. Let your eyelids droop slightly and blink as needed.