I haven't the cunting foggiest how to explain to someone else, in a language *I* understand poorly.
And if a mass occupies a point in space, which aside from the (hypothetical) point-like particle (which is zero-dimensional) then like other matter in space, it interacts with the time dimension. Weather from the 'point of view of' time, not that it can have a point of view, we, and the spatial 3D material universe, moves along at the same rate. A perception of time might differ, from a given individual's (I use the possessive) viewpoint, but to an external observer at an unchanging point, one that hypothetically could observe time yet not be affected otherwise (which doesn't exist in practice, to the best of my current knowledge), then two bodies separated by a fixed distance in time, would be 'seen' as moving in the same direction, in a fixed, unchanging ratio of distance between those two bodies.
That is to say, the past never gets a runup and toepunts the present in the nads from behind. The two do not crash into each other.
Zegh, when using 'motion', please do qualify when doing so in a topic like this, as it is important to state weather you mean motion in space, or along the time dimension.