It can be just a learner's habit, but I frequently (mis)use direct interrogative forms when I'm actually supposed to use indirect forms. Part of the reason is that it sometimes sounds even more natural to me, and other times I feel like even listeners understand my intent better in that way.
Let me leave an example below. Suppose my friend and I are traveling together and he saw me ask about something to a random person. When he asks me what I asked that person, I'd answer like this.
I asked him how can I get to the destination we're looking for.
Now this is using a direct interrogative form, but as far as I know, this is not so grammatical. I have to stutter every time to correct the right interrogative form, unfortunately. :(
But sometimes I come across occasions where even native speakers do this. The main reason why I auto-correct myself when doing this is because I thought it sounds so unnatural to native ears. Is it acceptable (or even idiomatic) in verbal conversations? Are there situations where I'm absolutely not allowed to use direct interrogatives? (in casual settings, not in a grammatical sense)