I saw a girl studying at a coffee shop and I thought she was beautiful.And a couple of weeks after I'd seen her studying at the coffee shop, I saw her dancing really hard at a club, when I thought she was so attractive that I
could not help but ask for her phone number.
could not help but ask her to give me her phone number.
I'm perfectly comfortable using "ask someone to ~" pattern, but I'd like to know if I can use "ask for~" in this context.