Either way, you want to make sure the flip is direct and to the player covering the bag. We had a SS who softly flipped the ball up on an arc (say 2 feet above the players head) towards the 2b during a state championship game two years ago. It cost us the DP to end the game with bases loaded. Got the runner coming into 2nd but did not get the third out at 1st. We were winning by 3 runs at the time with their stud hitter coming up to the plate.
Since it was a heart stopper for me as my kid was pitching, I will finish off the story...
So runner on 3rd scores, runners now on 3b and 1b. 2 outs. Stud hitter at the plate. Hit a homer earlier in the game and roped another one to the fence up the gap. We are now down by 2 runs. About the 3rd pitch runner on 1b steals 2b. So tying run is now in scoring position. A base hit wins the game. Kid ropes another down first base line. As he is running to 1st he slows his run to a jog and points both index fingers at my kid at the plate and mouths something to him. To this day my kid wont tell me what he said. Ump signals foul ball. Ball landed foul by about an inch. Of course parents are all yelling and screaming. Reset the field. I think the count was 2-2 on the batter at this point. My kid reaches back and fires the fastest ball I have seen him throw just above the knees on the inside corner to this batter. Batter never swings. He is rung up by the ump. Game over. Batter turns and starts unloading on the ump. Coach gets the kid off the field. He refuses to come out of the dugout to shake hands. Class player....