python 3.x – How do I shorten & optimize my Fibonacci Code?

Here’s the code I’m having trouble shortening. I am currently a beginner in Python 3.x.

from os import system

def fibonacci(terms):
    count = 0
    x = 0
    y = 1
    z = x + y
    if terms <= 0:
        print("Enter a positive integer.")
    elif terms == 1:
        print("Fibonacci sequence in " + str(terms) + " terms.")
        print(x)
    else:
        print("Printing " + str(terms) + " terms.")
        while count < terms:
            print(x)
            z = x + y
            x = y
            y = z
            count += 1

while True:
    user_input = int(input("How many terms? "))
    fibonacci(user_input)
    loop = input("Again? (Y/n) ")
    if loop == "Y" or loop == "":
        system("cls")
    else:
        exit()

I would appreciate if there will be someone who will be able to make this as efficient as possible. Thank you.