[Cromlyn]

What does the cue bid mean?

The bidding goes

2D (weak)
P
P
X
P
3D ?


And what would an immediate cue bid mean?

2D
3D ?

[kenrexford]

This is clearly a Xango sequence. If partner doubles your opening bid, you can cuebid your own suit as a lead - director inversion, asking for a lead of partner's running suit.

[SteveMoe]

First sequence suggests 4-4 Majors with just under strength or shape to make an initial takeout double.
Second sequence is either stopper ask or Michaels - prefer stopper ask.

[CSGibson]

SteveMoe, on 2013-December-31, 13:51, said:

First sequence suggests 4-4 Majors with just under strength or shape to make an initial takeout double.
Second sequence is either stopper ask or Michaels - prefer stopper ask.

I think your description of the first sequence is incorrect - it shows a 2-suiter with at least one 4 card major, may have longer clubs, and just under strength/shape to act initially.

I'm ambivalent about the 2nd, I can see reasonable arguments for a stopper ask with 8+ tricks (usually running suit), and for Michaels - I've heard strong arguments for Michaels, allowing 4♣ to be leaping michaels clubs and hearts, and 4♦ to be leaping michaels spades and clubs.

The real answer, though is it means whatever you define it as in your partnership. I think the answers I have given, however, are common treatments for advanced+ players who have discussed the situation.

[blackshoe]

CSGibson, on 2013-December-31, 16:20, said:

The real answer, though is it means whatever you define it as in your partnership. I think the answers I have given, however, are common treatments for advanced+ players who have discussed the situation.

My discussions with my partners about partnership agreements generally go "how about <whatever>?" "No. I'll never remember it."

Ain't getting old wonderful?

[awm]

With my partners I play:

1. The first 3♦ shows a game-forcing hand. This might be a hand with two places to play, but it also might just be a slam try (note that there are not many forcing calls available here). Doubler's first priority should be to show a four-card major, after which advancer can clarify the nature of his hand as follows: raise partner's major to show two places to play including the one partner named, make the cheapest suit call to show two places to play not including the suit partner named, cue to show slam interest in the suit partner named, anything else (usually a game bid in a new suit) to show some slam interest with a one-suited hand.

2. The second 3♦ shows a strong one-suiter. Advancer's first priority is to bid 3NT with a diamond control. Normally cuebidder will either pass 3NT next, or bid his single suit; removing 3NT to a single suit is a clear slam move. For Sam and me cue followed by 4M specifically denies a diamond control (direct 4M would be strong and guarantee a diamond control).

[Cyberyeti]

Does it make any difference if you play lebensohl here where 2♦-P-P-X-P-2N-P-3♣-P-3♦ is also in the frame ?

[TWO4BRIDGE]

2nd one ... the immediate 3D is a stop-ask ( 2-suiter bids are best handled by Roman-Jumps over a weak-2 ) :
( 2D ) - 3D!

the 1st one .... I've never encountered before:
(2D) - p - ( p ) - X
( p ) - 3D = max pass and I would guess it is asking for a major having 4-4 .