Cross-dressing is a fetish. That means you have recurrent, intense sexually arousing urges or behaviors that involve an inanimate object — in your case, women’s slips. Although not usual, and although some people would call it weird, it’s harmless unless it causes you distress or limits your life. If this behavior gives you pleasure and isn’t interfering in any way with your ability to be with a partner or to hold a job or do the things you have to do each day, then I wouldn’t be concerned. If, however, it causes you distress or gets in the way of your daily activities, then you should probably talk it over with a therapist.
I wish you well.