During oral sex the tongue moves up and down thus covering a distance that can easily be calculated on sexdistance.
In order to calculate the distance covered by the tongue we simply set the duration of the act and the times, one or more, that you want to measure for. So let's say that the duration was 15 minutes and it was done very fast, five times in total, this results in 207 meters which is actually quite a lot given the size of the average tongue!
It needs no explanation the fact that the sex distance of the giver is the same for the receiver - the tongue slides on something. Think about it!
Measuring ones sex distance is a fun thing to do and the fact that it is so easy to do it with sexdistance.com makes it almost imperative to do so. Have fun!