If the child is very young, the child will understand what you want if you extend your arms (put your arms out) and you can say:
- Come sit with Daddy / Come sit with Uncle Paulo
- Come here (which means "come sit with me".
- Come sit on my lap.
CurlyBrackets is correct. The terms for holding a baby close to you is called cuddling, but usually you would not use the word 'cuddle' because the child will not know what that means.
The action of holding/hugging someone (a child, your girlfriend, your wife) is called cuddling, but it not used when speaking to a child, however it would be OK if you said it to someone with a more advanced English understanding.
Hope this helps...