Stopering or Stoppering: How To spell?
The word Stopering is misspelled against Stoppering, which is present continuous of "Stopper"
Stoppering has double "pp" is mispronounced as "p"Remember double 'PP' in between the strings sto & ering which should not be misspelled with single 'P'
Wrong Spelling:  sto-p-ering  Correct Spelling:  sto-pp-ering 
Find more incorrect spellings of Stoppering to spell right way.