An FTM STP device is a hollow stand-to-pee prosthetic: a funnel cup seals over the urethra, and a shaft channels urine downward so you can pee standing up while still packing a bulge.
One wrong angle breaks the seal — which is why the first attempt usually happens in a shower, not at a urinal. The device solves a specific problem: peeing standing up while carrying a natural-looking bulge, without switching between two prosthetics.
STP stands for “stand to pee.” A hollow interior runs from a cup at the base through a shaft to an opening at the tip. Position the cup correctly and gravity does the rest; position it wrong and you get a leak.
What An FTM STP Device Actually Is
An STP device is a packer with a channel running through it. A standard packer is solid — bulge only. An STP adds a hollow interior, a cup or bowl at the base, and a shaft with a tip opening. Many models include a rim around the cup to cut splashback. Some are marketed as 2-in-1 or 3-in-1 (packing, peeing, sometimes play), but multi-purpose devices tend to be heavier or stiffer than a single-purpose packer.
How Does An FTM STP Device Work?
It works on a firm seal plus gravity: the cup presses against the body, urine flows through the channel, and the downward shaft directs it where you aim. The sequence matters more than the device:
- Seat the cup firmly against your body, over the urethra, so it seals with no gaps — gaps are the number-one cause of leaks.
- Angle the cup slightly forward rather than directly underneath you; it sits over the urethra, not the clitoris.
- Point the shaft downward toward the bowl or urinal. Gravity moves urine through the channel — fight it and you get leaks plus possible damage.
- Start with a slow, controlled stream. A gentle flow drains the funnel faster than it fills.
- Clear the channel when you finish, rinse the funnel and channel with water, lift the cup forward first (drops stay trapped inside), and wash daily with mild soap.
The slow-stream advice is mechanical: if the funnel fills faster than it drains, urine backs up and overflows — backflow is a limit, not a technique failure. Trans Guy Supply’s STP guide walks through this same order and recommends practicing in the shower first. No device is entirely leak-proof for all-day use, and STPs take repetition before the seal becomes automatic.
Where STP Devices Fit Into Daily Life
An STP works at a urinal or toilet and doubles as a daily packer between bathroom trips. You pack once in the morning and don’t swap prosthetics before walking into a restroom. Device selection drives most of the daily experience: cup size, shaft length, and material firmness affect how well the seal holds and how the bulge reads under clothing. If you’re weighing specific models, a tested roundup of the best FTM STP devices compares cup shapes and firmness side by side. Trimmed devices tend to be easier to position and clean; uncut or more detailed models can be harder to keep sealed. Whichever you choose, Trans Guy Supply’s explainer on what an FTM STP is covers construction differences in more detail.
| Situation | Best Approach | Why |
|---|---|---|
| First time using an STP | Practice in the shower | No cleanup pressure while you learn the seal |
| Public urinal | Aim shaft down, slow stream | Gravity does the work; a fast stream risks overflow |
| All-day packing | Keep the cup seated forward | Reduces leaks between bathroom trips |
| After every use | Rinse funnel and channel, lift cup forward | Clears trapped drops and leftover urine |
| Daily care | Wash with mild soap | Keeps the device hygienic for reuse |
Common Mistakes That Cause Leaks
Most STP failures trace back to one of three fixable mistakes:
- Angling the device upward. This causes leaks and can damage the device. Down is the only direction that works.
- Missing the urethra. The cup must sit over the urethra, not the clitoris, and slightly forward rather than directly underneath.
- Rushing the stream. The funnel only drains so fast. Start slow and stay controlled.
Compatibility is worth checking before you buy. These devices are marketed for trans men, transmasculine, and non-binary users, and body shape affects which cup style seals best. Transthetics’ product pages show how different designs approach the cup-and-channel layout.
Common Questions
Do I need to practice before using one in public?
Yes — practice in the shower first. Learning where the cup seals over your urethra and how slow your stream needs to be takes repetition, and a shower removes the cleanup pressure. Most people need several attempts before the seal becomes reliable.
Can an STP device replace my regular packer?
For many people, yes. An STP can be worn for daily packing and used for standing to pee, so you don’t swap prosthetics between bathroom trips. Multi-purpose models may be heavier or stiffer than a dedicated packer, which changes how they sit under clothing.
Why does my STP leak even when I follow the steps?
Check the seal and your angle first. Gaps around the urethra and an upward-tilted shaft cause most leaks. If the funnel fills faster than it drains, backflow follows — slow your stream. No device is entirely leak-proof for all-day use.
Sources
- Trans Guy Supply. “What Is an FTM STP?” Explains STP construction and how the cup, channel, and shaft work together.
- Trans Guy Supply. “FTM STP Guide: Stand-to-Pee Device” Covers positioning, stream control, and post-use cleaning steps.
- Transthetics. “Transthetics Official Site” Product pages showing how different STP designs approach the cup-and-channel layout.