I just began to drink a shake consisting of fast carbs and protein,
I sip it during my workout.
Should I have a another shake after the workout? And if yes, should i sip it or drink it all as soon as my workout end.
I would say no. Drinking it during the workout is basically the same as drinking it after. I hope you are drinking Surge, cause if not, it really doesn't matter.
I take two scoops of Surge and mix it into just under two liters of water with 5g of creatine. I'll start it during the session and polish it off at the end.