OK, out of curiosity,

I have two male fixed indoor only 1 year old cats. They rarely get in
serious fights (I think) but they do tend to play fight a bit, which
usually ends with my smaller cat holding his ground while my larger cat
runs away.

The only time i see them mutually grooming is before a fight. Usually,
while one is sleeping, the other comes over and starts licking, and the
other starts licking back. But after a minute or so, one starts biting,
then the other starts biting, until finally there is some growling in
pain because one is biting too hard. Eventually they are swatting and
chasing each other.

So my question is - why do they groom each other if it always ends in
fighting? Is it possible for them to groom without fighting? Do they
"like" each other? Thanks!