STP Compatible
Cake Bandit · Trans-Owned · STP Ready
Pack it. Pee in it.
Or Neither. No Rules.
STP-compatible underwear, harnesses, and pouches for trans men, trans masculine, gender expansive, gnc, and non-binary people. Every piece in this collection is built to work with an STP — but works just as well with a packer, or nothing at all.
All Cake Bandit STP underwear is flat-front
No bulge built in. The flat-front cut is designed to work with whatever you're packing — an STP, a soft packer, a hard packer, or absolutely nothing. You choose. The underwear doesn't choose for you.
What's in this collection
Flat-Front Briefs & Boxers
Built-in STP positioning with a flat front. Briefs, boxer briefs in 3" and 6", jockstrap, and long underwear styles. All Cake Bandit, all flat-front.
Wear Your Own Underwear
Jockstrap, O-ring, slingshot, and brief harnesses. STP-ready O-ring opening positions your device correctly — in whatever underwear you own.
Clip-On STP Pouch
No new underwear required. The STP Packing Pouch clips directly to existing waistbands and holds your STP or packer in place all day.
Pick by how you want to use it
| Style | STP-ready? | Packer-ready? | Wear your own underwear? |
|---|---|---|---|
| Cake Bandit STP Briefs / Boxers | ✅ Yes | ✅ Yes | No — all-in-one |
| Cake Bandit STP Jockstrap | ✅ Yes | ✅ Yes | No — all-in-one |
| O-Ring Harness | ✅ Yes | ✅ Yes | ✅ Yes |
| Jockstrap / Slingshot Harness | ✅ Yes | ✅ Yes | ✅ Yes |
| STP Packing Pouch | ✅ Yes | ✅ Yes | ✅ Yes — clips to any waistband |
Complete Your Setup
Do I have to use an STP with this underwear?
Not at all. Every piece in this collection is designed to be STP-compatible — but the flat-front cut works just as well with a soft packer, a hard packer, or nothing in it. There's no built-in bulge, no padding, no expectation. You wear it how you want.
What's the difference between STP underwear and a harness?
STP underwear replaces your underwear entirely — it's all-in-one. A harness lets you use whatever underwear you already own and adds STP or packer compatibility on top. Both hold your device securely all day. It comes down to whether you want a complete solution or a flexible add-on.
Which TGS STPs work with these harnesses?
All TGS house STPs — the STP Freely, STP Freely XL, and The Lou — are compatible with O-ring harnesses. The key is positioning: your urethra needs to align with the STP's urethral opening, not your clitoris. Read our STP Guide for full positioning details.
How do I size Cake Bandit underwear?
Cake Bandit sizes by hip/waist measurement: XS 24–26", S 27–31", M 32–35", L 36–38", XL 39–42", 2XL 43–46", 3XL 47–52". When in doubt, size up. If you pack heavy or want a snugger hold for your STP, size down. Questions? Email hello@transguysupply.com before ordering.
Are underwear and harness sales final?
Yes — all underwear, harness, and STP sales are final for hygiene reasons. We strongly recommend measuring before ordering and reading individual product descriptions carefully. If you're unsure, reach out before you buy.
