I was leading the route. On reaching and clipping the belay chain I simply clipped my lead rope into an in situ caribiner as my partner was intending to lead the route after me. I then called to my partner to let him know I had done so, however instead of shouting 'take' or 'clipped' as I normally would in this situation, I accidentally shouted 'safe'. Furthermore, the rope my partner was holding was at this point unweighted as I was pulling down on his end of the rope on the opposite side of the chains from myself. My partner immediately took me off belay. At this point we were both simply holding the lead rope in our hands. I started to lower myself, luckily still holding on to the rope that was running up from my belayer. He then realised, something was up and shouted up to let me know I was off belay. I quickly held on tighter to the rope and he quickly got me back on belay. I'd just avoided a 25m fall!