# I suppose the word order matters
firstword = 'peck'
secondword = 'peppers'
mystring = 'Peter Piper peppers picked a peck of pickled 某个东西 peppers. Where\'s peppers the peck of pickled 四川 peppers Peter Piper picked?'

# get split the string on firstword, gives you a list
mylist = mystring.split(firstword)
# after splitting on firstword, the phrases we are interested in begin with a space
# now find phrases which begin with a space and contain the second secondword
# split on secondword and save the first element of the new list
myphrases = []
for phrase in mylist:
    if phrase[0] == ' ':
        newlist = phrase.split(secondword)
        # get rid of leading and trailing whitespace
        result = newlist[0].strip()
        myphrases.append(result)

print('found text between', '"' + firstword + '"','and ', '"' + secondword + '"', len(myphrases), 'times')
for p in myphrases:
    print(p)

import re

mystring = 'Peter Piper peppers picked a peck of pickled peppers. Where\'s peppers the peck of dozens of pickled peppers Peter Piper picked?'

findit = re.search(r'peck(.*?)peppers', mystring).group(1)

print(f'One occurance  -> {findit}')

findit = re.findall(r'(?:peck)(.*?)(?:peppers)', mystring)

print(f'Multiple occurances - > {findit}')

Output:
One occurance  ->  of pickled 
Multiple occurances - > [' of pickled ', ' of dozens of pickled ']

print('found text between', '"' + firstword + '"','and ', '"' + secondword + '"', len(myphrases), 'times')
# With f-string
print(f'found text between "{firstword}" and "{secondword}" {len(myphrases)} times')

Output:
found text between "brown" and  "lazy" 1 times
found text between "brown" and "lazy" 1 times

>>> import re
>>> 
>>> text = 'The quick brown fox jumps over the lazy dog'
>>> result = re.search(r'quick(.*?)jumps', text)
>>> result.group(1)
' brown fox '
>>> # Fix whitespace
>>> result.group(1).strip()
'brown fox'