In order to measure this we first have to make some assumptions about the average penis size, the average duration and the average speed. So let's start the calculation. Medical studies have shown that the average penis size is 13cm we assume a penetration depth of 11cm. As the average duration we'll take the average time from entering the vagina to ejaculation - no foreplay. The average duration is found to be 11min.
Furthermore we need to set a number of relationships for each. For the sake of simplicity let's say three different partners for each one, an average of two months duration of each relationship and an intercourse frequency of every second day. This frequency yields almost 15 times per month.
The total number of times is: three relationships per person x two months per relationship x 15 times per month = 90 times. Finally we'll set the speed to "Normal" first and to "Fast" later.
Feeding the above values to the Sexdistance interface gives 4.76 kilometers in normal speed and 6.35 kilometers in fast. These numbers obviously are not the same for everyone and total sex distance varies among different people as it is based purely on average values and not in exact ones. Every individual should measure his/her own sex distance on sexdistance.com.
It needs no explanation the fact that the sex distance of the giver is the same for the receiver. In this particular case the distance covered by the penis inside the vagina is equal to the distance travelled by the vagina around the penis. (Remember the piston image.)
Measuring ones sex distance is a fun thing to do and the fact that it is so easy to do it whith sexdistance.com makes it almost imperative to do so. Enjoy sex, enjoy life!