Not to get more out of a benzo (or in my case sometimes Flexeril), but to treat medical issues, plugging can be a godsend. I've always battled ulcers and I can usually keep my stomach in check now through a good diet and yogurt daily. I have to keep on this regularly though or I'm in major pain and I won't be able to keep anything down.
But when I neglected a healthy diet, and let it get out of hand, I've plugged Flexeril when I've been suffering from severe back spasms. Man, the first time I plugged Flexeril, I was in so much pain, and I was praying that it would work (just 10mg too). Sho nuff, the muscles relaxed and I got some sleep after being in agony for hours. I'll never forget how relieving that experience was. Felt like taking a stay-well dose when you're really dope sick.
I don't know about getting any more out of benzos/muscle relaxant by plugging. I didn't notice any increase in strength with muscle relaxants or benzos. But the onset seems faster.
So, yeah, there are definitely practical reasons for plugging. Whatever works when you're in pain, or if you're having a panic attack and you're stomach/GI won't let you keep anything down.
btw, Shambles, thanks for letting folks know about oil-solubility and benzos. And Z-drugs too, right? Most pluggers use some kind of lube anyhow so whats a little olive oil? Comfort and safety first.
RIP Tobala. A great gentleman sorely missed.