One of the most-searched donation questions, and one of the simplest answers: there is no restriction. Donating 450 mL does not make sex unsafe, impossible or harmful — the same day or any day.
Why the myth exists
Every culture wraps donation in more caution than medicine requires — no exercise, no alcohol, no sex, no lifting. The medically real list is short: hydrate, eat well, skip the gym for a day, no heavy lifting on the donation arm for a few hours. Sex was never on the medical list; it joined by folklore.
The only genuine advice
Some donors feel a little tired for a few hours — blood volume shifts back within a day. If you feel fine, you are fine. If you feel tired, rest first; anything energetic can wait for the evening without any medical consequence.
What actually matters after donating
Water, the free biscuits, a proper meal, and no heavy lifting with the donation arm. Everything else — work, walking, travel, and yes, intimacy — is yours to do as normally as you feel.