Every week it is like torture for all three of us. My 15 months old son screams and thrashes around, somehow he hates it. We try to distract him, with head massage or some far relative cutting it, but every trick works once or twice, and the problem starts again.
I know the usual method is to cut it while he is asleep, but his room is quite dark, and his bed is very deep.
I would appreciate any advice.
The clipping from a clipper might be scaring him. If you're using the latter try scissors instead. You might also have hurt him in the past with one or the other. If so, consider a switch to scissors from clipper or vice versa to see if the new method makes any difference.
In case you're not doing so already, nails (like hair) are more flexible and thus easier to cut when wet so be sure to cut nails shortly after a bath.
Likewise, try showing him you doing it to yourself if you haven't done so already. Sit him on your lap while you do yours. This'll drive the point that others including yourself do it too, and should reassure him that it's safe in case he feels nervous about it.
Speaking of position, see if a new one might make a difference: with him on your lap facing the same direction as you do, the same with him facing you, at his side, in front of him.
Lastly, are you sure you're not hurting him? If not and you usually cut them very short, try leaving the nails a little bit longer. Also, a clipper flattens the nail somewhat if you cut the entire thing in one go, which can be scary and potentially painful, so try clipping in more steps instead.
What we do is cutting the nails while asleep, but we'll always announce it beforehands. We believe, that it's important to be clear about your intentions and anything else could break the trust your child has in you. It works quite fine, since the bed of our daughter is directly attached to ours (similar to a Rollaway). If it's a bed with a lattice on the side you could try and grip through the lattice to cut the nails. Regarding the room being dark: I usually use a torchlight or the flash in my phone, which works quite well.
There are other strategies, such as letting your child see how you cut your nails on each other, to build up confidence that it's nothing bad. Some other parents from our kindergarten told us, that they had their daughter getting her nails done professionally (no french manicure - I hope) and the issue dissolved afterwards (rather for girls or parents who do not care much about gender clichées).
Here is what I do with my 9 month old:
Ever since she was a newborn she has been listening to a playlist of children songs every day, and she grew really fond of it. When nail cutting is needed, I allow her to watch the animation of the first song (which is the time we need for cutting), while holding her in my lap facing the same way. She would transfer her look back and forth between the screen and her nails, but would not object to me cutting. I use special child scissors with rounded tip. (This is the playlist, btw: https://www.youtube.com/watch?v=fdjKZdQSlFE)
(Note: Like all babies/children, she is naturally attracted to the screen. However, she does not otherwise get screen time, be it computer or TV -- we actually do not even own a TV --, except for when skyping with far away relatives. That said, I feel that for the nail cutting purpose, 2-3 minute exposure once a week is worth it.)
