No worries bro, for the grinding pattern, also got solution one. But after they know the trick, they may have countermeasures next time, so always improvise and control.
Sit up, hug them tight, don't let go, lie down again (still hugging them) and arc your backwards...........cup their butt cheeks with both hands and pull them forward towards you if necessary.
Another way, is sit upright, hug them (one arm warp around her back, stronger hand on one butt cheek, and forearm to carry her weight), throw your body weight forward towards her, rise to kneeling position (all in one fluid motion), then fall towards her, and you will be in the missionary position leow (depending on space constrain lah).
Remember to support the back of her neck, very important (use the palm of the hand that you use to warp around her back)
Caution: Don't sikal bang her head on the wall or ledge of bed:(
To last longer, close your eyes and fully concentrate counting to 100:p, clear of all lovemaking images in your mind.
Some when they know you wanna come will not upstroke. They will sit on you and do the rapid "forward and backward" motion.
That pattern is a killer lah...