Delta Hedging Mental Block understand, already, against, position, long

LBriscoe

It has always been intuitive to me how a dealer that writes call options or put options can obtain a hedge on the exposure to these securities by taking offsetting long and short underlying positions, respectively.

What I cant seem to fathom is in the case where you have a long position in the underlying already - dont fully understand how you can hedge the value of this long position (protect against downward price movements) by "shorting a call"- I thought that when you short a call you are selling/writing it and it is only the holder of the instrument that is securing any payoff what so ever and the writer is subject to only the downside of the stock price increase.

Again I understand that a short call will increase in value if the price drops (which is what you are seeking) but I associate a short call position with selling/writing a call and so my perception is the only payoff you would get is the premium you received up front and its does nothing to hedge! Color me confused.