This is amazing and an awesome idea to carry your pets by motorcycle more fun with your friend together but you need to keep in mind full safety measures that cause no danger or accident.
A tank carrier has a magnetic property on the bottom of the bag and your motorcycle needs a magnetic tank so the bag can stick easily. I never recommend you to drive with your pet with a magnetic bag it can’t hold a good amount of weight. Riding with your pet on the bike with a magnetic bag tank is not much safe if your pet is rowdy.
Some bags have given strips that you can attach to the handlebar and leg bar somewhere manually. This will be a hassle to turn your bike handle and cause more risk of an accident and you may also face issues riding your bike.
I do a lot of research and found that not that type of bags companies are manufacturing and selling, rarely can find you one with magnetic or strips but it is not safe for small dogs or large.
Ride with your pet very safe and secure with no risk. I found the best motorcycle tank dog carrier bag. You need to hang the bag by your shoulder and your pet will easily sit on the bike tank to ride the enjoy without any worry.
To make an enjoyable ride with your friend. I would suggest you put goggles on your friend, will look cute and his eyes will safe from dust and air.
I wish you a happy ride with your pet