Analysis of Suppose

Suppose, my dear, that you were I
 And by your side your sweetheart sate;
Suppose you noticed by and by
 The distance 'twixt you were too great;
Now tell me, dear, what would you do?
 I know--and so do you.

And when (so comfortably placed)
 Suppose you only grew aware
That that dear, dainty little waist
 Of hers looked very lonely there;
Pray tell me sooth--what would you do?
 I know, and so do you.

When, having done what I just did
 With not a frown to check or chill,
Suppose her red lips seemed to bid
 Defiance to your lordly will;
Oh, tell me, sweet, what would you do?
 I know, and so do you.