BDSM
I am sure there is at least one sac tied up in there 
I like to tie them really tight, so the skin gets shiny because it is stretched so tight. You ust have to keep an eye on them and don't let them get too purple
I liked the pics you have on your website. I really like the one where the cock & sac are tied in three sections. I believe that is what my client wants.
What kind of rope do you use? And how tight do i tie it?
I don't want to hurt my client 
I like to tie them really tight, so the skin gets shiny because it is stretched so tight. You ust have to keep an eye on them and don't let them get too purple
K
I use climbing rope and cord fr my bondage, but to do something like that you can use a shoe lace, pretty easy
I like to tie them tight enough that they start turning purple, but go with your client's reactions...I am always talking to my play partner (if it is someone I don't know well) and checking with them about what's too tight, too loose, etc. (which doesn't mean I don't take it a little beyond what they say 
) so ask him if it is too tight, and remember that as you tie it will get tighter.
Have fun