I don’t know how many times this search term has landed on this site (numerous), but it’s obviously something I need to address. The following is from my book, The Honor Guard Manual. Complete information about the aiguillette can be found here and it can be purchased here (#683RO is actually my design that I created with Wendy Lazar in 2009).
Even though this is my DrillMaster Uniform, the principles of the aiguillette are the same. The rope should be centered on both shoulder seams, where the “T” meets. The pin should be removed from the rope so that you will then have to pin it from the inside of the blouse (FYI: a blouse is a uniform jacket) using a large diaper pin or something similar.
In this picture you see that my uniform has epaulets that are just forward of the shoulder seam so I have to center my aiguillette on the epaulet, your aiguillette must be centered at the 12 o’clock position.
A look at the inside of the left arm of my blouse: One pin at 9 o’clock (holding the aiguillette at the back of the shoulder) and I use two pins at 3 o’clock (holding the aiguillette and the tassel right next to each other- no space- at the front of the shoulder). These pins are used to ensure that the top half of the rope is completely flush with the blouse- pull the rope tight when pinning it, but not tight enough to cause a gap.
Any questions? Please ask!