East wants to play this in 4 of a Major. You can make 11 tricks without help from the defence in either Major and only 9 in No Trumps.

You could transfer to Spades then rebid 4♥ over West's 3♠ but you only show a 5-4 shape. Although you end in 4♠ making 11 tricks you still end in 4♠ if West had 3 Hearts and 2 Spades and miss the 5-3 Heart fit.

There is a better way. If partner denies a 4-card Major after you bid 3♣ to ask for one then use 4♣ to ask for a 3-card Major.

For those of you playing 5-card Puppet Stayman the same applies using the sequence 2NT - 3♣ - 3NT (no 4-card Major) - 4♣ .