Fastenings ...

Unless you are in a unitard or a one piece, 

or in an obnoxiously colored spandex suite

the chances that your costume is going to have some sort of fasten is pretty high. Whether they are the snaps on contemporary blue-jeans or clamping apparatus's from the nineteenth century it is easy to forget just how much we depend on them to keep others from seeing our pink spotted underwear.

On stage we depend on these types of safeguards just as much as anyone else does in society, so in the costume studio it is important to understand how one would secure these small accessories to our outerwear.

1. Hook and Bar

These types of fastenings are generally used at single points like near the waistband thought they can also be used to to close entire openings.

When deciding where to place these items on your fabric or clothing item it is important to remember not place them too close to the edges as this may  result in leaving a space or gap between your fabrics. Similarly you would not want to place them too far away from the edge of the fabric as this could lead to an uncomfortable actor in, now, too tight pants.

Once you are ready to begin sewing remember that you will want to double thread your needle, giving  the stitch more strength against the forces acting against the fasten.

TIP: Make sure you place a knot at the end of your now double threaded thread. It took me nearly a whole minute to figure out as to why my own thread was not making to proper stitch like everyone else...save yourself the embarrassment.

You will want to first sew the loops (or eyes) on the ends of both the hook and bar. Begin threading from the opposite side of the fabric from your hook or bar and loop with your thread around the curvature at the ends. Repeat five or six times (possibly more if you feel the hook or bar in not fastened tight enough) and then knot off the end of your thread once it has been cut.

Secured bar.
(Don't mind the little extra bit of thread, a bit of a mishap.)

For the hook you will want to loop an extra few times around the long end of the small piece of metal, this is so it can be better secured.

Secured Hook.

Once this is complete you or your actor can then fasten and unfasten your pants just as much as you like. Though preferably in private.

2. Snap Set

I quite enjoy snaps. Though this may possibly have nothing to do with sewing than as it does with the sound your voice makes when you say it. 

In any case.

Snaps are used, generally, on clothing such as jackets and the like and are rarely visible once fastened. The set has two items a ball and a socket, or if you prefer a male and a female. Because the male (Ball) has an extension that  resembles...well, you know; and the female (socket) has an resembles...you know, the other thing.

When you are ready to secure these pieces into the fabric you will once again double thread your needle (be sure to knot it, we know where that can lead us). As with the eyes of the hook and bar you will want to loop the open spaced and the outer rim of the item as well as repeat five to six times. When moving from space to space that needs to be looped make sure you begin from the underside of your item and not going over it.

Ball

Socket