Need 5 minutes for some reason? Tummy time, they are going to cry because its hard, but its good exercise. While my Doctor of Physical Therapy wife would not exactly recommend leaving the room for some legal purpose… Your kid is probably going to be crying for 5 minutes during tummy time, you are going to hear silence if something is wrong. For a normal baby, you can start tummy time at 2 days old. My favorite process is: Baby is crying, put them in tummy time for 5 minutes while I get the bottle ready, feed them the bottle, put them to bed. (If someone wants to be famous, do a scientific study to see how 5 minutes of tummy time, 3x per day affects SIDS rates)
Baby proof an area. We fenced off our entire living room with a baby/pet fence for our first kid. This peace knowing there was nothing dangerous they could get into, gave us freedom to do work in the kitchen. We might have overpaid for our baby fence, but it was well worth it. At 3 kids, the entire home is already baby proofed, so we don’t use fences or gates too much.
Teach your baby to hold the bottle. If our baby was in daycare, they learned this quickly. Basically when the baby is strong and coordinated enough to play with the bottle, its time to start teaching them to hold the bottle. The type of bottle you use may impact this, some bottles are easier to hold than others. Put their hands on the bottle and let go. Do this for a few weeks during feedings and bottle feedings just became recreational rather than necessary. My wife and I can attest to how much fun it is to bottle feed before bed as our usually hyper baby passes out in our arms.
Don’t rock your baby to sleep (every time). That 10-20 minutes you spend rocking your baby to sleep is time that your baby could be learning to fall asleep by themselves. I recently received a text message from a friend that asked ‘at what age do kids sleep without rocking them?’ referring to their 2 year old. I start this when the baby is a few weeks old, especially if the baby is fed, changed, and burped.
Do chores with the baby, especially when they are fussy. A baby carrier is best if you are planning on a long session, but even one handed chores are more productive than doing 0 chores. Moving around, I imagine your baby will no longer be fussy, plus you can hand them random objects to look at.
Exercise with the baby present. Stroller running is reasonable for a mile or so on pavement. You can hula hoop, jump rope, spin bike, and lift weights all a few feet from the playroom, depending on your setup. You can even stretch with your baby on top of you. I would lower your expectations for this workout, it should be considered a supplementary workout. Babies are unpredictable and might just start balling their eyes out causing you to stop halfway.
Have some breast feeding plans. My wife sent emails, checked facebook for freebies, did online shopping, listened to audiobooks, and of course endless social media scrolling. Point being, you can have quality multitasking time that are either enjoyable or productive or you can waste it. Have a plan.
Use baby monitors. Between our home security cameras and all of my laptops/tech devices, I can watch and communicate with the kids throughout the house from the toilet.
In disagreement with the non-scientific World Health Organization who used opinions to form their recommended 0 seconds of TV per day, I recommend letting your under 1 year olds watch phonics and count to 100 videos. By age 2, they will automatically associate letters with sounds and can begin learning to read, they will know numbers to 100 and be able to begin adding. I throw in a Periodic Table of Elements song and similar songs into the mix. Consider this is monumentally better use of screen time than showing your kids corporate mascots(Disney/Nintendo/etc…)
The Kid’s Grandparents can be a good way to soak up a few hours. On a similar note, I have cousins that love babies and will give us an hour or so of freedom.
Siblings are going to be teammates for life, get them into it early. Most kids can attempt a ‘shake the rattle/be silly for the baby’ and confuse the baby into being calm for a moment. This only needs to work once before the bond is formed. The bond of course being the selfish relationship that ‘playing with baby = crying stops’. I think your goal as an efficient parent is to facilitate the kids enjoying each other so playing is automatic.