How would you guys count semiquavers and higher subdivisions in a compound meter?
Currently I just count |1 & a 2 & a 3 & a etc... quavers and approximate higher subdivisions
for:

time 6/8/clef treble / c8 c16 c16 c8 c8 c8 c8

'1 coffee tea 2 and a.'

time 6/8/clef treble / c8 c32 c32 c16 c8 c8 c8 c8

'1 pickle cheese tea 2 and a.'

so the pulse is 1 rest rest 2 rest rest
6 quavers are 1 and a 2 and a.
two 16ths are coffee
two 32nds followed by a 16th is pickle cheese,
if the 16th comes 1st then cheese pickle.
four 32nds are caterpiller
quintuplets are hippopotamus
sextuplets are widdly diddly
7 over four is chubby hippotamus

It's the same principle as with simple meter.

If you are in 6/8, counting Quavers like this:

1 & a 2 & a

then semiquavers are twice the speed/half the duration (however you want to look at it):

1 e & a & a 2 e & a & a

Try tapping quavers with your right hand at a medium tempo, if you then tap your left hand in between those taps to double the feel, you have semiquavers.
Quote by Matt.Guitar
It's the same principle as with simple meter.

If you are in 6/8, counting Quavers like this:

1 & a 2 & a

then semiquavers are twice the speed/half the duration (however you want to look at it):

1 e & a & a 2 e & a & a

Try tapping quavers with your right hand at a medium tempo, if you then tap your left hand in between those taps to double the feel, you have semiquavers.

Thanks, much appreciated.