The union of the Sun & Moon.
The product of the promordial essence conveyed by the trunk of Ida & Pingala resulting in Shakti joining Shiva in the Bridal Chamber.
Passing on the journey up the Tree through the Ajni where the virgin is clothed in preparation for the meeting with the bridegroom.
The problem with some methods is that the bride does not enter the chamber in a submissive manner (in its proper context), but tears through the veil unannounced and with such force that all hell breaks loose, resulting in a state of bewilderment or worse.
In other words; rituals are not for nothing.