from tkinter import *


def hiirevajutus(event):
    print(event.x," ", event.y)
    ala.coords(ovaal, event.x, event.y, event.x+d, event.y+d)

aken=Tk()
ala=Canvas(aken, width=400, height=300, bg='white')
ala.pack()

x=10
y=100
d=15

ovaal=ala.create_oval(x, y, x+d, y+d, fill="blue")
ala.bind('<Button-1>', hiirevajutus)

aken.mainloop()