|NO! Not this kind of slingshot!|
Once engaged by your unsuspecting target (he's busy thinking you're his kill) the first thing he will do if he's a good pilot is try to pull parallel with you, to match heading and staying at your side, working to prevent this exact maneuver, usually somewhere between 16-24 KM from your ship. First thing is first, get him in the right position for the slingshot. Turn directly away from him, and as your stern(ass) spins around to face him(mooning him), you activate your MWD, as if you are attempting to escape. Pull range like mad, as if trying to escaping, heading for 26+ km, or 30+ if he has a faction point. It may be a good idea to try to align towards something you can warp out to just in case you do get out of point range and want to bail quickly before he recovers point.
Now with him "behind" and your MWD helping you extend the range from him, he will turn as well, trying to bring you back to his kiting range of 18-24 km. To close the distance faster he'll light off his MWD, this is where having velocity on your overview pays off. Wait for him to build some speed/inertia with the MWD or AB. Usually this is somewhere between 900-1200+m/s, or enough speed to start closing the distance between you and him, the deeper he "bites" the better luck you will have catching him at the end of this maneuver. Use a little judgement and at the right time, when he's committed to closing range, that is when you control-space to kill your forward boost, but leave your MWD active, waiting for your speed bar to drop just below the 3/4 tick mark on your HUD, giving your ship the best chance at a fast rate of turn. Repeatedly click approach target towards him, leaving your MWD active.
Now you are turning towards him and he is still burning towards you, the range between you should be dropping quickly, faster as you gain speed towards him. The easy way is to continue to mash the approach button, but this is not the best way, there is a chance he will correct and the wasted time you try to go directly at him let's him escape. The harder way it's going to take some practice. Try to eyeball where his path is going to take him in space and where you can be to bring him to a Closest point of Advance, then aiming for where he is now. You just need that CPA to be inside of your scram/web range so 11-14km.... Now don't forget to overheat your MWD/Scram/Web for extra speed and extra range on your tackle. Once he slings himself inside of your scram web range, apply DPS and tackle, don't let him out... Alive.