We were playing 5CM strong NT. I wanted to bid 3♦ at my second turn to show a good hand with spade support but it is likely that would confuse partner, and in the past she has interpreted 3♠ in analogous auctions as invitational. When 4♦ came round to me I took partner for a minimum opener and decided opponents have gone too far so hit it. We can get it three off but I or we didn't find the perfect defence but +300 was a top as everyone else is playing in a major partscore or going off in game.
They got their revenge with interest on the next two boards:
Board 2:
I made a mistake in the defence and let this through (I should have led a club later in the play but tried to endplay declarer in case he held the club king and blew a trump trick. Partner didn't provide a signal to suggest a potentially useful club card. I should have played one anyway, if declarer had the club king I am endplayed and it makes no difference). That was worth 10%. One pair played in 4♦X=, two were in 3♦, one took 1♠ one off.
Board 3:
Opponents bid to 6♥ on these cards making which was worth 10% for us. Only one other pair found the heart slam, one went off in 6♠, the rest were in game.
My defence still needs some work and I am not quite managing to use the available information optimally to find the best play.