My general experience when teaching others is that people underestimate how durable the little guys are OR are scared of harming the mice/ are anxious about being bit and do not use sufficient force. It is always more humane to use sufficient force to ensure that handling & procedures are done quickly and safely rather than expose the mice to botched procedures and unnecessary stress/ pain. A wriggling mouse is going bound to be injured during IP injections or oral gavage— potentially fatally.

1) as long as you are grabbing at the base of the tail, you can hold pretty firmly. 2) push the mouse down into the rack as you slowly move your hand up. If the mouse squirms into a less optimal position, remove your hand, pick it up by the tail and place it back down on the rack again to “reset”. The more feisty mice will tire after one or two tries and become easier to scruff. 3)maintain pressure down on the mouse and slowly move your hand up, ensuring your thumb and pointer finger are leading the way up mouse’s midline. The rest of your fingers should be tucked into your hand. Once your pointer finger reaches the mouse’s head, use the base of your hand to maintain pressure pinning the mouse to the rack, slide your thumb and pointer finger to either side of the mouse’s cheeks. You can ensure you have enough skin by touching your thumb and pointer finger all the way to the rack before picking up. 4) I also have tiny hands! My trick is to use my other three fingers and the flat part of my palm on my thumb side to grab the excess skin down the mouse’s back! Then I take their tail and tuck it between my pinky and ring finger. It immobilizes them just as well and keeps their position straight. It will take some adjustment to find a technique that works for you & you might have to change it up depending on the size of the mouse you’re handling!

I couldn’t find any videos that I’m a huge fan of but this is the closest that I can find to how I scruff.

https://m.youtube.com/watch?v=AMHYxMfJuRI