lie on your back bend your knees up with feet flat on floor, raise your bum and lower back so your almost up on your shoulders/middle back and squeeze your bum and hips up slightly, you should feel this in your pelvis then release . it's quite a gentle exercise and do about 10/15 reps , hope it works!
You can do pelvic floor exercises anytime just by tightening the muscles that you pull in to stop weeing mid-wee! Do reps of about 10-15 fast then pull them in and hold for about 10 secs.