Synchronizing your breathing with your partner is not only a useful technique for controlling ejaculation, but also a way to enhance intimacy.
Joint breathing practice Breathing deeply together (chest to chest, eye contact) for a few minutes before sex prepares the nervous system for calm, controlled arousal.
Verbal cues: A partner can remind you, either aloud or in a whisper, to “breathe slowly”—this is often more effective than reminding you on your own during times of intense arousal.
Why it's mutually beneficial Slow, synchronized breathing also enhances the feeling of connection for your partner—benefitting both of you, not just "solving" one's problem.
Practical advice for beginners Practice first in a separate, non-sexual context (meditation, yoga) to make it easier to use this technique naturally during intimate moments.