Since i came across the same Question and found this Thread but no Awnser, i decided to try myself and found the solution. So if maybe someone get the same problem again or you are still looking for an awnser here is how to do it:
-> Navigate to Plugin Editor
-> Choose the Ocean Product Sharing Plugin
-> On the ride side, open template and click on product-share.php
-> press STRG+F and search for the Text (in my case it was Tweet this Product)
-> You will find the text and then can change it to whatever you like
-> Save and enjoy
