I have seen it from a sentence in an eye drop instruction manual. Here it is.
かつてない気持ちいい、さし心地...それは、極小一滴だから!
In my opinion, I translate it as "the very feeling" by referring 「さし」from a source that it is a prefix used to emphasize the following word, in this case is 「心地」. Therefore, the whole word 「さし心地」 would function as stressing the previous one 「気持ちいい」to inform that it will really help making the user feel great after using it.