Anyone having/had a blessing at their wedding?

Neither my fiancee and I are religious therefore are wanting to steer clear of any religious setting. We plan to marry officially in a registry office a couple of days before the actual wedding with both of our parents present. We then plan to have a blessing ceremony on our wedding day and have it conducted by my brother. We want to know how this works really? We've heard bits and peices about it, that you can have your vows altered to your preference ect some have mentioned the tying of ribbons to bind you as one which I think sounds interesting. Has anyone had experience with this before or perhaps attended a blessing ceremony themselves? Thanks.