How to make this call?

[DTQ_Blue]

Sitch from last night. Team at bat was behind 1-0 at the time,

R1 attempts to steal 2B. I'm in B and move into position. The catcher's throw is to the 1B side slightly and as F4 (inside the runner's path) takes the throw R1 goes into her slide a little early. This causes her extended leg to come up about 2" short of touching second base (not hard to see when you are on top of the play, but I'm not sure if anyone else could see it). The tag is applied high on the chest and to the offensive coach in the 3B dugout, it looks like the runner got under the tag. I simply give an out call with no other mechanic or verbal.

Coach comes out to discuss and I tell her that the runner never reached second base. Between innings, my partner tells me that the tag was late and that he could have helped me out. I tell him that the runner never touched the bag and he said, Oh, OK.

So my question being that the offensive coach and my partner thought that I blew the call, is there a mechanic that I could have used to immediately communicate why I called the runner out? I think that would have prevented the ensuing dialog with the coach and my partner.

BTW, the coach's team put up 5 in the B6th and won the game 5-1. I will be working their game next Wednesday.

Thanks,
Mike