Here is a space-picture of how the meteors of this stream cross Earth’s orbit.
The picture shows the courses of several particles with slightly different orbital elements, to suggest the vastness of the stream in space. Earth’s collecting of a relative few of them is like a bullet passing through a cloud of gnats. We show the Sun 10 times larger than it really is, Earth 500 times, so even the line representing Earth’s course is thicker than the real Earth.
Properly, the particles are “meteoroids” when they are hurtlint through outer space; they become “meteors” if and when they hit our atmosphere and vaporize with flashes of light, or “meteorites” in the even rarer chance that they survive to be found as lumps somewhere on Earth.
They are bits of dust or rock that separated from the asteroid 3200 Phaethon, so they still approximately follow its orbit. The diagram shows their courses over a span of 120 days, centered on their perihelia (nearest points to the Sun). Red indicates the parts of the orbits south of the ecliptic plane. Those passing us now will pass closest to the Sun in July. Shortly after that, they return northward through the ecliptic plane, then fly on out, to return about 20 months later.
They approach us from outside and north of our orbit. It is the angle between these approaching paths and our own December path that causes them to appear to radiate from the direction that we call the constellation Gemini.
Hers is the Geminid radiant appearing above the northeastern horizon early in the night. The meteor trails shown are of course schematic; they can be in any part of the sky (tending to appear longer in more distant parts), but you know they are Geminids if you can trace them back to near the Twin stars. The hazy band of light is the Milky Way; the imaginary “Earth’s shadow” is at the point opposite to the Sun.
The Geminid shower is nowadays perhaps the year’s most reliably abundant; you could see 50 an hour, or more, during its most intense hours. It is convenient also (for people in Earth’s north hemisphere) because the radiant is in the sky for the whole of this long near-midwinter night. True, it is liable, like most meteor showers, to be best in the after-midnight hours: the radiant keeps climbing higher (parallel to the “motion of the sky” arrow on the celestial equator) until about 2 AM. If you are up and out about that time, you are facing into the Geminid stream, and you are around on the front side of your planet as it curves along its course around its star.