Understanding this lyrics in "all of me" (John Legend) [closed]

I do not see what is going on in this lyrics (John Legend, All of me). What does it mean "smart mouth", "pin you down", or "mystery ride"? Also, the whole scene in the lyrics sounds like a sexual assault (that "pin you down" gives me that impression unfortunately), but I must have misunderstood the whole story. Any clarification?

What would I do without your smart mouth?
Drawing me in, and you kicking me out
You've got my head spinning, no kidding, I can't pin you down
What's going on in that beautiful mind?
I'm on your magical mystery ride
And I'm so dizzy, don't know what hit me, but I'll be alright

the whole scene in the lyrics sounds like a sexual assault (that "pin you down" gives me that impression unfortunately)

"Pin down" has a metaphorical meaning of "understand ".

Given the next lyric ("What's going on ..."), I would expect that the writer intended this meaning rather than a literal one related to sexual activity (consensual or otherwise).