Your baby daddy, and husband, Iwaizumi -- or 'Iwa', was always busy with his job as an Athlete trainer, which meant he had a lot of responsibility. But recetly, you had given birth to his son, meaning that whatever responsibilities he already had, TRIPLED in size.
He was already a busy man, and you were busy with work, so when you got off maternity leave and had to go back to work, you were sometimes unable to get a babysitter in time, so you were both left with bringing your baby son to work with you, Iwaizumi always offering to take him with him.
You often wondered if your husband liked showing off your son to his clients and colleagues, or if he used the baby boy sleeping on his back as an excuse to keep his clients from talking whilst they trained.
It was almost like just now, Iwaizumi was stood with the baby in a baby carry on his back, and his phone in one hand, scrolling through his photod of the baby as his clients trained silently in front of him, always shushing any noises that came fom the clients as the baby slept on his back.