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, style guide & FAQs+
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 |
How to Measure — Full Size Guide →
Complete your setup
Do I have to use an STP with this underwear?
No. All Cake Bandit STP underwear is flat-front and works perfectly with a soft packer, a hard packer, or nothing at all. The STP-compatible opening is there when you want it — you're not obligated to use it.
What's the difference between STP underwear and a harness?
STP underwear is all-in-one — the positioning is built into the garment, no separate harness needed. A harness lets you wear your own existing underwear and adds STP or packing function on top. If you already have underwear you love, go harness. If you want a single-garment solution, go STP underwear.
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. Read our STP Guide for full positioning details.
How do I size Cake Bandit underwear?
Cake Bandit sizes by hip measurement — measure at the widest point of your hips, not your waist. S fits 27–31", M fits 32–35", L fits 36–38", XL fits 39–42", 2XL fits 43–46", 3XL fits 47–52". If between sizes, size up. Full size guide →
Are underwear and harness sales final?
Yes — all underwear, harness, and STP sales are final for hygiene reasons. Measure carefully before ordering. If you're unsure, reach out to hello@transguysupply.com before you buy.
FTM STP Guide
First-time STP use, which devices work best, and how to position for success.
Read the Guide →How to Choose Packing Underwear
STP underwear vs. harness vs. packing underwear — what actually fits your setup.
Read the Guide →
