The Bed-Spreader Under the Mattress Restraint System

Explore a new realm of intimacy with the Sei Mio Bed Spreader - a premium under bed restraint system crafted for couples seeking enhanced connection, control, and creative play. Designed to slide effortlessly beneath your mattress, this fully adjustable bed harness transforms any standard bed into a discreet and thrilling playground of pleasure.

Whether you're a seasoned explorer or just starting to experiment with restraint-based intimacy, this versatile and easy-to-use set of under bed restraints offers a comfortable, secure way to indulge your fantasies.

Why Choose the Sei Mio Under Bed Restraints?

Universally Adjustable Fit

The Sei Mio bed harness system is designed with convenience in mind. With adjustable straps that extend to accommodate any bed size from single to super king. This under mattress restraint system is compatible with virtually every bed type, ensuring a snug and secure fit beneath your mattress.

Discreet & Effortless Setup

There’s no need for bedposts or complicated assemblies. Simply slide the central strap under the mattress, position the extensions to your liking, and you’re ready to go. When not in use, the entire system tucks away easily, perfect for maintaining privacy without compromising on readiness.

Comfortable, Padded Restraints

Each set includes soft yet strong wrist and ankle cuffs, fully adjustable to suit all body types. The padding ensures comfort, even during longer sessions, while the strong velcro closures keep your partner safely restrained without discomfort.

Built for Pleasure and Durability

Crafted from high-quality nylon webbing and durable hardware, this under bed restraint system is made to last. Whether you enjoy gentle exploration or more intense experiences, the sturdy design supports all levels of adventurous play.

Enhance Trust and Intimacy

For many couples, introducing under mattress restraints can deepen trust, boost communication, and unlock new levels of mutual pleasure. The Sei Mio Bed Spreader invites you to connect on a deeper level, emotionally and physically.

Perfect for Beginners and Experienced Users

Whether you're looking to gently introduce power dynamics into your relationship or add variety to your already playful bedroom routine, this bed harness provides a reliable, user-friendly way to enhance your intimacy. With minimal setup and maximum excitement, the Sei Mio under bed restraint system lets you focus on what truly matters pleasure, trust, and shared experiences.

• Fully adjustable four-point under-the-mattress restraint system
• Fits single, double, king and super king beds
• Easy to install and discreetly store when not in use
• Central carabiner design with removable straps for multiple restraint positions
• Soft padded adjustable cuffs for added comfort
• Quick-release hook and loop fastenings for easy adjustment
• Detachable cuffs can also be used independently as wrist or ankle restraints

Adults Only

Position the restraint straps beneath your mattress, keeping the central ring roughly centred before pulling each strap out from the sides of the bed.

Attach the padded cuffs, fasten them securely around the wrists and ankles, then adjust the strap lengths to achieve your preferred level of movement and restraint.

This product is designed for adult use only and should always be stored securely, well out of the reach and view of children.

• Fully adjustable straps create a secure, customised fit
• Soft padded cuffs provide enhanced comfort during use
• Modular strap system offers versatile positioning options
• Designed to fit a wide range of bed sizes and furniture setups
  

Materials

• 53% Nylon
• 23.5% Metal
• 16.5% Polyester
• 7% PVC

Discreet Delivery From Sei Mio

Your privacy is important to us. Every order is shipped in plain, unbranded packaging with nothing to indicate what is inside.

UK Delivery

Orders placed before 1pm, Monday to Friday excluding Bank Holidays, are dispatched the same day. Orders placed after 1pm, over the weekend, or on Bank Holidays are sent on the next working day. Delivery options are shown at checkout, with parcels sent via Royal Mail or Interlink Express.

European & International Delivery

European orders are delivered using Royal Mail, while international shipments are handled by Interlink. Shipping costs are calculated based on the size and weight of your order and are displayed at checkout.

Please note that orders placed outside the UK may be subject to import duties or local taxes. These charges are set by your local customs authority and are beyond our control.

Returns & Refunds

Unused and unopened items can be returned in their original packaging within 30 days for a full refund.

To arrange a return, please contact us on +44 (0)1636 703454 or email sales@seimio.com to request a returns form. Refunds will be issued to the original payment method once the item has been received and checked. Please allow up to 14 days for the refund to appear.