Major impurity may follow ejaculation or the legal threshold of intercourse. Once that threshold is met, the rule does not depend on whether semen is emitted.
Thus penetration meeting the legal definition independently requires ghusl.
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Why Ghusl Follows Intercourse without Ejaculation
Causes Requiring Ghusl and the Sunnah Baths
Major impurity may follow ejaculation or the legal threshold of intercourse. Once that threshold is met, the rule does not depend on whether semen is emitted.
Thus penetration meeting the legal definition independently requires ghusl.