thrash your arms about like you just don't care
You jump into the pool and you start to flail your arms and legs in a wild fashion. With frenetic quantities of thrashing, you manage to stay afloat. Or so you thought. You sink to the bottom. Panic ensues. Someone kindly pulls you out of the water where you gasp and cough and hack your lungs out.
don't think. feel.
Think of any skill you have. Let's take driving - shift down a gear, while pressing the clutch and steering the vehicle while continuing the conversation you are having. If we have to think and communicate, it will take far too long. Instead, it is a pattern ingrained in us by practice.