Lovesync is a pushbutton system for romantic partners. Each partner gets a button. When one of the partners wants sex, they push the button. Nothing happens unless/until the other partner pushes their own button within a specified time window, then both buttons glow green. Lovesync is about 50% funded on Kickstarter.

Lovesync reminds me of a proposal someone told me about in the 1980s as a way to keep discussion salons interesting. Everyone would be given a handheld gadget with a button. When someone was talking, anyone could secretly push the button if the person talking was boring them. If over 50% of the people pressed the button, a buzzer would go off, meaning the speaker had to stop talking,