How do I insert text between existing words?

When writing on Android, z. For example, on YouTube comments, I sometimes have to change the word order or insert words. Cutting an existing word is easy: just long press on the word and select "Cut". However, I had difficulty inserting the test in the right place.

For example, suppose I have copied "malicious" to the clipboard and would like to paste it into an existing sentence "I have seen a dog". between "a" and "dog". When I try to press the space between "a" and "dog" long, the word "dog" is selected. I can then choose "paste", but then the current selection is replaced by it, which I do not want. I can not search for a word anyway without picking something.

I use Gboard (Google Keyboard).