for this one , make sure u got the nollies on lock , (really?) but unlike a regular lip slides where u have some grip has you pop that makes you go left to right or right to left for and make a lip slide.your. what you need to practice is nollies where you pop side ways ,where your hips make you got side to side instead than your legs and feet.try a couple 180s like that on a roller and see if you feel the trick a little better. let says that the rail is at your right , has you pop the nollie , bring your hips a little bit on your right.you can start by comming in the rail whit a angle which makes it easier. the more you wait between the pop and the rotation the higher nollie is gonna be . has for, more hight the rail gets the more patient yo need be for bringing your feet at 90 for the slide position. i hope thats answers it for you let me know if you need more info or if its all chinese for you.