Method for treating fibrous substrates with compositions comprising silicone copolymers of the formula where Y is identical or different and denotes a divalent hydrocarbon radical which has 1 to 20 carbon atoms and may comprise one or more heteroatoms, preferably oxygen or nitrogen atoms, Z is identical or different and denotes an organic radical which contains a polyoxyalkylene group and is divalent, preferably a radical of the formula - (R 6 O) w -R 7 -, R 1 is identical or different and is a radical of the formula -N(R 4)-R 5 (IV') or -O-R 5 (V'), R 2 is identical or different and denotes a monovalent hydrocarbon radical which has 1 to 18 carbon atoms and may comprise halogen or oxygen atoms, R 3 is identical or different and is a hydrogen atom or a monovalent hydrocarbon radical having 1 to 20 carbon atoms, R 4 denotes a hydrogen atom, a C 1-18 alkyl radical or a hydrocarbon radical which has 4 to 18 carbon atoms and comprises one or more oxygen or nitrogen atoms, and R 5 denotes a C 1-18 alkyl radical or a hydrocarbon radical which has 4 to 18 carbon atoms and comprises one or more oxygen or nitrogen atoms, or R 4 and R 5 in formula (IV') together denote a divalent hydrocarbon radical which may comprise one or more oxygen or nitrogen atoms, R 6 is identical or different and denotes a C 1 -C 10 alkylene radical, preferably a C 2 -C 3 alkylene radical, more preferably an ethylene or isopropylene radical, and R 7 denotes a C 1 -C 10 alkylene radical, preferably a C 2 -C 3 alkylene radical, more preferably an ethylene or isopropylene radical, n is an integer from 10 to 2000, preferably 10 to 300, p is an integer from 1 to 5, preferably 1 to 2, more preferably 1, and w is on average 2.5 to 80, preferably 10 to 30. Y is identical or different and denotes a divalent hydrocarbon radical which has 1 to 20 carbon atoms and may comprise one or more heteroatoms, preferably oxygen or nitrogen atoms, Z is identical or different and denotes an organic radical which contains a polyoxyalkylene group and is divalent, preferably a radical of the formula - (R 6 O) w -R 7 -, R 1 is identical or different and is a radical of the formula -N(R 4)-R 5 (IV') or -O-R 5 (V'), R 2 is identical or different and denotes a monovalent hydrocarbon radical which has 1 to 18 carbon atoms and may comprise halogen or oxygen atoms, R 3 is identical or different and is a hydrogen atom or a monovalent hydrocarbon radical having 1 to 20 carbon atoms, R 4 denotes a hydrogen atom, a C 1-18 alkyl radical or a hydrocarbon radical which has 4 to 18 carbon atoms and comprises one or more oxygen or nitrogen atoms, and R 5 denotes a C 1-18 alkyl radical or a hydrocarbon radical which has 4 to 18 carbon atoms and comprises one or more oxygen or nitrogen atoms, or R 4 and R 5 in formula (IV') together denote a divalent hydrocarbon radical which may comprise one or more oxygen or nitrogen atoms, R 6 is identical or different and denotes a C 1 -C 10 alkylene radical, preferably a C 2 -C 3 alkylene radical, more preferably an ethylene or isopropylene radical, and R 7 denotes a C 1 -C 10 alkylene radical, preferably a C 2 -C 3 alkylene radical, more preferably an ethylene or isopropylene radical, n is an integer from 10 to 2000, preferably 10 to 300, p is an integer from 1 to 5, preferably 1 to 2, more preferably 1, and w is on average 2.5 to 80, preferably 10 to 30.