I am interested in the literal meaning of くすぐったい. If くすぐったい is equivalent to the English expression, "That tickles!" (said by someone being tickled), what is the literal meaning of this word? If it is an adjective stemming from the verb くすぐる, would it literally mean "I want to tickle!"? Is there a logic behind the use of the -tai form adjective ( expressing desire ) that I am not getting?
Translation requires context. In additional to "tickles", it may also mean "embarrassing": そんなに褒められると擽ったい.
From the verb kusugur- (擽る, to tickle), the adjective kusuguttai describes the situation of being tickled. Note that there is also kosogur- and kosoguttai.
As the desiderative -tai, this would become kusuguRItai. Rather, this is another -(t)tai suffix that expresses 1) extremeness and 2) situational. There are both -tai and -ttai forms. Other examples include atubottai, bottai, habattai, harebottai, hirabettai, hirattai, kemutai, kemuttai, kutihabattai, medetai, tumetai, usirometai, usubettai, uzattai, yabottai, zirettai.