The concept of finding strong sexual undertones to every romantic poem may be a more recent intellectual pursuit based on Freudianism. Though he may have never really said it, ‘sometimes a cigar is just a cigar.’ One can easily tell from the tenor of the Old Testament that what occurs under the coverings of the marriage bed, or the thoughts of what might occur under them, is never considered a noble subject for embellishment or innuendo, at least to the degree that one might find in Greek or other pagan poetry, where not only apples are fair play but undertones of desire for young men, by older men, could even be found.
Sex in the bible is not shamefully repressed, but rather treated with taste and healthy discrimination, knowing that since the fall sex has become degraded in many forms and in some aspects should not be spoken of with respect to its details. At the same time sex between man and wife does symbolize the love between the Son and the Bride in the New Testament as even the names imply. Even under the Old Testament there are a few risqué statements that show a healthy and unashamed view of sex while not turning into a wild fantasy resembling pagan literature or sexual poems. For example, the command to be ‘satisfied with the breasts’ of the wife of ones youth always being intoxicated with her love (Proverbs 5:19) shows a lack of repression or avoidance of sexuality but a healthy assertion that would even embarrass us today (the so called sexually liberated), if we were to mention this advice to our boss at work, for example.
Given that the Bible never divulges the erotic movements hidden under the bed sheet, and at the same time does not shy away from sexuality, it seems we must find a tasteful balance if we are to seek sexual imagery underlying the Song of Solomon. If we think we can treat it just like Greek poetry we have abandoned all sound exegesis as ancient Hebrew and Greek views of appropriate sexual insinuations and innuendos, let alone actual behaviours, could not be further apart.
To answer the question then, as Euphemism is often a tasteful way to refer to sex, such as the example in proverbs where intoxication might be euphemistic for sex, it seems reasonable to assume some modest use of eumphemism in the Songs of Solomon. But I do not see any reason to assume the particular verse you mention has any direct sexual meaning. Even When using our Christian context of the bride and groom there is no reason to go beyond the spiritual meaning as expressed here:
Oh, taste and see that the Lord is good!
Blessed is the man who takes refuge in him! (ESv Psalms 34:8)
Taking comfort in the shade of a fruitful tree and enjoying its fruit seems no different from the Psalmist. I can't imagine anyone thinking this has a hidden sexual overture in either location. Besides what I do not like about thinking there is, is that this would naturally wander into the subject of oral sex, since the key word is 'taste' and this seems very far outside the cast of scripture for the forementioned reasons.