How do you insert the penis into the vagina?

In my case, in the missionary and woman on top positions, my partner usually uses her hands to guide it in.

Sometimes, i put the head of my penis between her buttocks and move it up until it starts to slip in.

Very seldom, things line up and I can just thrust it in. This happened once in a side by side position and took my partner by surprise and was immensely exciting.

I am interested in hearing other techniques.

Most times my wife guides me in, sometimes I just aim and get in on my own

Starting by some kind of foreplay either with oral, toy, or fingers to get some sort of lube started.

For inserting , rubbing the tip of my penis over her vulva from top to bottom in a downward direction guiding into the vagina.

This always seems to work in any position for a comfortable start for both of us. When I lost my virginity, which wasn't planned ( just happened). I was guided in having trouble finding the vagina because of all the pubic hair she had in the dark.

For the second time she was trimmed very short which was much more enjoyable.