Unsound bidding

The bidding goes like this (dealer is North a.k.a me):

My holdings:

• S : A K Q J 10 X
  
• H: X X X
• D: J X
  
• C: X X

I was tempted to open 1 S but well, I decided to give it a miss since I'm the first seater with slightly below 12HCP, seeing how the bidding goes.

N: Pass, E: Pass, S: Pass, W: 2c (21 and above HCP),
N: 2S (I decided to overcall with solid spades and minimal losers), E: 3D, S: 3S(my partner shows some spade support), W:4NT(Ace asking),
N:5S(I was feeling naughty and decided to kajiao their ace asking with 5S since my partner showed some spade support and we are not vulnerable), E: 6NT?! ( Holy shit?!?!?!), S: Pass, W: Pass,
N: DOUBLE!!!!! FREE POINTS!!!!

I managed to cash my solid spade suit and defeat the contract easily, winning 1400 points. Well, the point here is to play sound bridge. No matter how unsound my bid is, actually I would not bid 6NT with no spade stoppers, knowing I will lead spades. This is sheer insanity and thank god, insanity is working in our favor. =)