Hi there ~
I do not see a question here as you seem to have answered it yourself. However you seem to be judging whether intrusion or intercourse would be a good term for anal penetration. Well I have just used a different term, and I wonder if it would suit your terminology needs. That being said, any kind of unsafe sex, especially anal and oral sex
are not safe and brings with them a whole lot of different kind of infections/organisms that are not suitable in the genitalia. I hope this answers your question.
Take care and have a lovely day!