Aspitation after S

I know consonants are not aspirated after S, but is it always so? It's not, because in a recent thread here most people said they aspirate the C in "disclose", so it's dis-close, and not di-sclose. Well, how do I know whether to aspirate them after S's or not? Any rules of thumb?

I thought of "never aspirated, unless the S is part of a suffix or another word in a compound word". So you have mi-stake and di-stract, and on the other hand you have mis-tune, mis-treat... The only problem is there are words like "disclose". Unless you consider "dis-" as a suffix.. hmm.

I know about the no-aspiration after /s/ but is that true for other languages?

Anyway, with regard to your question, I do not aspirate in words like "disclose" or "distract." However, this not true for constructions such as "He has two guitars." In "has two" I aspirate.

In my language there's no aspiration in any case, as far as I know, so I had to learn about aspiration in English. But this is not part of my question. :-)

I understand that you aspirate in "has two", but those are two separate words, so I have no doubts in those cases. What I am interested in are words with SP, ST, SK sounds in them. Can you think of any words where you aspirate after an S? More importantly, can anyone think of a rule of thumb for aspiration after S? Thanks.

Phonologically, it depends on whether the [s] and its preceding consonant are in the same syllable or different syllables. So I have:

mistake [məˈsteɪk]
distract [dɪˈstɹækt]

mistune [ˌmɪsˈtʰuːn]
mistreat [ˌmɪsˈtʰɹiːt]
disclose [dɪsˈkʰlɤʊz]

The question this raises, though, is just what is driving such distinctions in syllabification, considering that syllable boundaries are not normally phonemic in and of themselves. The only thing I can think of is that such is being really determined by morpheme boundaries, with "mistake" and "distract" having been reanalyzed as monomorphemic but "mistune", "mistreat", and "disclose" still being treated as multimorphemic.

Yeah, I think I'll aspirate the consonant after S only if the S is part of an obviously separate suffix or attached part.